Method for transmitting and receiving signals in wireless communication system and device therefor

ABSTRACT

The present invention relates to a method for transmitting and receiving channel quality information in a wireless communication system for supporting a Narrowband Internet of Things (NB-IoT) and a device therefor and, more particularly, the method comprising: transmitting and receiving a random access preamble; transmitting and receiving a random access response on the basis of the random access preamble; and transmitting and receiving channel quality information via a narrowband physical uplink shared channel (NPUSCH) on the basis of the random access response, wherein when the random access preamble is transmitted and received on the basis of a narrowband physical downlink control channel (NPDCCH) order in a radio resource control (RRC) connected state, the channel quality information is measured on the basis of a UE-specific search space (USS) set in the RRC connected state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application under 35 U.S.C. § 371of International Application No. PCT/KR2019/010169, filed on Aug. 9,2019, which claims the benefit of Korean Application No.10-2019-0017870, filed on Feb. 15, 2019, Korean Application No.10-2018-0134002, filed on Nov. 2, 2018, Korean Application No.10-2018-0115383, filed on Sep. 27, 2018, Korean Application No.10-2018-0114554, filed on Sep. 25, 2018, Korean Application No.10-2018-0114490, filed on Sep. 21, 2018, and Korean Application No.10-2018-0093416, filed on Aug. 9, 2018. The disclosures of the priorapplications are incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, to a method and apparatus for transmitting andreceiving downlink (channel) quality information.

BACKGROUND ART

Mobile communication systems were developed to provide voice serviceswhile ensuring mobility of users. However, mobile communication systemshave been extended to data services as well as voice services, and moreadvanced communication systems are needed as the explosive increase intraffic now leads to resource shortages and users demand higher speedservices.

Requirements of the next generation mobile communication systems are tosupport accommodation of explosive data traffics, dramatic increases inthroughputs per user, accommodation of significantly increased number ofconnected devices, very low end-to-end latency, and high energyefficiency. To this end, various technologies such as Dual Connectivity,massive multiple input multiple output (massive MIMO), in-band fullduplex, non-orthogonal multiple access (NOMA), support of superwideband, and device networking are under research.

DISCLOSURE Technical Problem

An aspect of the present disclosure is to provide a method and apparatusfor efficiently transmitting and receiving downlink (channel) qualityinformation.

Another aspect of the present disclosure is to provide a method andapparatus for efficiently transmitting and receiving downlink (channel)quality information in a random access procedure.

Another aspect of the present disclosure is to provide a method andapparatus for efficiently transmitting and receiving downlink (channel)quality information in a radio resource control (RRC) connected state.

Another aspect of the present disclosure is to provide a method andapparatus for efficiently transmitting and receiving downlink (channel)quality information about a physical downlink control channel (PDCCH)and/or a physical downlink shared channel (PDSCH).

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present disclosure could achieve will be more clearlyunderstood from the following detailed description.

Technical Solution

In an aspect of the present disclosure, a method of transmitting channelquality information to a base station (BS) by a user equipment (UE) in awireless communication system supporting narrowband Internet of things(NB-IoT) includes transmitting a random access preamble to the BS,receiving a random access response from the BS, and transmitting thechannel quality information to the BS through a narrowband physicaluplink shared channel (NPUSCH) based on the random access response. Whenthe random access preamble is transmitted based on a narrowband physicaldownlink control channel (NPDCCH) order in a radio resource control(RRC) connected state, the channel quality information is measured basedon a UE-specific search space (USS) configured in the RRC connectedstate.

In another aspect of the present disclosure, a UE configured to transmitchannel quality information to a BS in a wireless communication systemsupporting NB-IoT includes a radio frequency (RF) transceiver, and aprocessor operatively coupled to the RF transceiver. The processor isconfigured to transmit a random access preamble to the BS, receive arandom access response from the BS, and transmit the channel qualityinformation to the BS through a narrowband physical uplink sharedchannel (NPUSCH) based on the random access response, by controlling theRF transceiver. When the random access preamble is transmitted based onan NPDCCH order in an RRC connected state, the channel qualityinformation is measured based on a USS configured in the RRC connectedstate.

In another aspect of the present disclosure, an apparatus for a UEconfigured to operate in a wireless communication system supportingNB-IoT includes a memory including instructions, and a processoroperatively coupled to the memory. The processor is configured toperform specific operations by executing the instructions. The specificoperations include transmitting a random access preamble to a BS,receiving a random access response from the BS, and transmitting channelquality information to the BS on an NPUSCH based on the random accessresponse. When the random access preamble is transmitted based on anNPDCCH order in an RRC connected state, the channel quality informationis measured based on a USS configured in the RRC connected state.

Further, the channel quality information may be determined based on amaximum repetition number configured for the USS.

The channel quality information may be determined based on a repetitionnumber required to detect a hypothetical physical downlink controlchannel at a specific block error rate (BLER).

Further, the specific BLER may be 1%.

When the random access preamble is transmitted in an RRC idle state, thechannel quality information may be measured based on a common searchspace (CSS) used to receive the random access response.

Further, the channel quality information may be determined based on amaximum repetition number configured for the CSS.

The channel quality information may be measured for a non-anchorcarrier.

Advantageous Effects

According to the present disclosure, downlink (channel) qualityinformation may be efficiently transmitted and received.

Further, according to the present disclosure, downlink (channel) qualityinformation may be efficiently transmitted and received in a randomaccess procedure.

Further, according to the present disclosure, downlink (channel) qualityinformation may be efficiently transmitted and received in a radioresource control (RRC) connected state.

Further, according to the present disclosure, downlink (channel) qualityinformation about a physical downlink control channel (PDCCH) and/or aphysical downlink shared channel (PDSCH) may be efficiently transmittedand received.

It will be appreciated by persons skilled in the art that the effectsthat can be achieved with the present disclosure are not limited to whathas been particularly described hereinabove and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiments of the disclosure andtogether with the description serve to explain the principle of thedisclosure. In the drawings:

FIG. 1 is a diagram illustrating physical channels and a general signaltransmission procedure in a 3^(rd) generation partnership project (3GPP)system;

FIG. 2 is a diagram illustrating a random access procedure;

FIG. 3 is a diagram illustrating long term evolution (LTE) radio framestructures;

FIG. 4 is a diagram illustrating a slot structure in an LTE frame;

FIG. 5 is a diagram illustrating a radio frame structure in a new radioaccess technology (NR) system;

FIG. 6 is a diagram illustrating a slot structure in an NR frame;

FIG. 7 is a diagram illustrating cell coverage enhancement in machinetype communication (MTC);

FIG. 8 is a diagram illustrating MTC signal bands;

FIG. 9 is a diagram illustrating scheduling in legacy LTE and MTC;

FIG. 10 is a diagram illustrating transmission of narrowband Internet ofthings (NB-IoT) downlink physical channels/signals;

FIG. 11 is a diagram illustrating a signal flow for an initial networkaccess procedure and a subsequent communication procedure in an NRsystem;

FIG. 12 is a diagram illustrating transmission of a preamble on anNB-IoT random access channel (RACH);

FIG. 13 is a diagram illustrating a time flow of channels and signalstransmitted/received by a user equipment (UE) in a random accessprocedure;

FIGS. 14 to 17 are flowcharts illustrating methods performed in a UE anda base station (BS) according to proposals of the present disclosure;and

FIGS. 18 to 23 are block diagrams illustrating a system andcommunication devices to which proposed methods of the presentdisclosure are applicable.

BEST MODE

In the following description, downlink (DL) refers to communication froma base station (BS) to a user equipment (UE), and uplink (UL) refers tocommunication from the UE to the BS. In the case of DL, a transmittermay be a part of the BS, and a receiver may be a part of the UE. In thecase of UL, a transmitter may be a part of the UE, and a receiver may bea part of the BS.

The technology described herein is applicable to various wireless accesssystems such as code division multiple access (CDMA), frequency divisionmultiple access (FDMA), time division multiple access (TDMA), orthogonalfrequency division multiple access (OFDMA), single carrier frequencydivision multiple access (SC-FDMA), etc. The CDMA may be implemented asradio technology such as universal terrestrial radio access (UTRA) orCDMA2000. The TDMA may be implemented as radio technology such as globalsystem for mobile communications (GSM), general packet radio service(GPRS), or enhanced data rates for GSM evolution (EDGE). The OFDMA maybe implemented as radio technology such as the Institute of Electricaland Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX),IEEE 802-20, evolved UTRA (E-UTRA), etc. The UTRA is a part of auniversal mobile telecommunication system (UMTS). The 3rd generationpartnership project (3GPP) long term evolution (LTE) is a part of anevolved UMTS (E-UMTS) using the E-UTRA. LTE-advance (LTE-A) or LTE-A prois an evolved version of the 3GPP LTE. 3GPP new radio or new radioaccess technology (3GPP NR) or 5G is an evolved version of the 3GPP LTE,LTE-A, or LTE-A pro.

Although the present disclosure is described based on 3GPP communicationsystems (e.g., LTE-A, NR, etc.) for clarity of description, the spiritof the present disclosure is not limited thereto. The LTE refers to thetechnology beyond 3GPP technical specification (TS) 36.xxx Release 8. Inparticular, the LTE technology beyond 3GPP TS 36.xxx Release 10 isreferred to as the LTE-A, and the LTE technology beyond 3GPP TS 36.xxxRelease 13 is referred to as the LTE-A pro. The 3GPP 5G means thetechnology beyond TS 36.xxx Release 15 and 3GPP NR refers to thetechnology beyond 3GPP TS 38.xxx Release 15. The LTE/NR may be called‘3GPP system’. Herein, “xxx” refers to a standard specification number.The LTE/NR may be commonly referred to as ‘3GPP system’. Details of thebackground, terminology, abbreviations, etc. used herein may be found indocuments published before the present disclosure. For example, thefollowing documents may be referenced.

-   -   3GPP LTE    -   36.211: Physical channels and modulation    -   36.212: Multiplexing and channel coding    -   36.213: Physical layer procedures    -   36.300: Overall description    -   36.304: User Equipment (UE) procedures in idle mode    -   36.331: Radio Resource Control (RRC)    -   3GPP NR    -   38.211: Physical channels and modulation    -   38.212: Multiplexing and channel coding    -   38.213: Physical layer procedures for control    -   38.214: Physical layer procedures for data    -   38.300: NR and NG-RAN Overall Description    -   38.304: User Equipment (UE) procedures in Idle mode and RRC        Inactive state    -   36.331: Radio Resource Control (RRC) protocol specification

Evolved UMTS terrestrial radio access network (E-UTRAN), LTE, LTE-A,LTE-A pro, and 5^(th) generation (5G) systems may be generically calledan LTE system. A next generation radio access network (NG-RAN) may bereferred to as an NR system. A UE may be fixed or mobile. The term UE isinterchangeably used with other terms such as terminal, mobile station(MS), user terminal (UT), subscriber station (SS), mobile terminal (MT),and wireless device. A BS is generally a fixed station communicatingwith a UE. The term BS is interchangeably used with other terms such asevolved Node B (eNB), general Node B (gNB), base transceiver system(BTS), and access point (AP).

A. Physical Channels and Frame Structures

Physical Channels and General Signal Transmission

FIG. 1 is a diagram illustrating physical channels and a general signaltransmission procedure in a 3GPP system. In a wireless communicationsystem, a UE receives information from a BS on DL and transmitsinformation to the BS on UL. The information transmitted and receivedbetween the UE and the BS includes data and various types of controlinformation. There are many physical channels according to thetypes/uses of information transmitted and received between BS and theUE.

When a UE is powered on or enters a new cell, the UE performs initialcell search including acquisition of synchronization with a BS (S11).For the initial cell search, the UE synchronizes its timing with the BSand acquires information such as a cell identifier (ID) by receiving aprimary synchronization signal (PSS) and a secondary synchronizationsignal (SSS) from the BS. The UE may further acquire informationbroadcast in the cell by receiving a physical broadcast channel (PBCH)from the BS. During the initial cell search, the UE may further monitora DL channel state by receiving a downlink reference signal (DL RS).

After the initial cell search, the UE may acquire more detailed systeminformation by receiving a physical downlink control channel (PDCCH) andreceiving a physical downlink shared channel (PDSCH) corresponding tothe PDCCH (S12).

Subsequently, to complete the connection to the BS, the UE may perform arandom access procedure (see FIG. 2 and a related description) with theBS (S13 to S16). Specifically, the UE may transmit a random accesspreamble on a physical random access channel (PRACH) (S13) and mayreceive a PDCCH and a random access response (RAR) to the preamble on aPDSCH corresponding to the PDCCH (S14). The UE may then transmit aphysical uplink shared channel (PUSCH) by using scheduling informationincluded in the RAR (S15), and perform a contention resolution procedureincluding reception of a PDCCH and a PDSCH corresponding to the PDCCH(S16).

After the above procedure, the UE may receive a PDCCH and/or a PDSCHfrom the BS (S17) and transmit a PUSCH and/or a physical uplink controlchannel (PUCCH) to the BS (S18) in a general UL/DL signal transmissionprocedure. Control information that the UE transmits to the BS isgenerically called uplink control information (UCI). The UCI includes ahybrid automatic repeat and request acknowledgement/negativeacknowledgement (HARQ ACK/NACK), a scheduling request (SR), and channelstate information (CSI). The CSI includes a channel quality indicator(CQI), a precoding matrix indicator (PMI), a rank indication (RI), andso on. In general, UCI is transmitted on the PUCCH. However, if controlinformation and data should be transmitted simultaneously, the controlinformation may be transmitted on the PUSCH. In addition, the UE maytransmit the UCI aperiodically on the PUSCH, upon receipt of arequest/command from a network.

FIG. 2 is a diagram illustrating a random access procedure.

The random access procedure is performed during initial access in RRCidle mode (or RRC_IDLE state), during initial access after radio linkfailure (RLF), during handover requiring the random access procedure, orupon generation of UL/DL data requiring the random access procedure inRRC connected mode (or RRC_CONNECTED state). The random access proceduremay also be referred to as a random access channel (RACH) procedure.Some RRC messages such as an RRC Connection Request message, a CellUpdate message, and a URA Update message are also transmitted in therandom access procedure. Logical channels, common control channel(CCCH), dedicated control channel (DCCH), and dedicated traffic channel(DTCH) may be mapped to a transport channel RACH. The transport channelRACH is mapped to a physical channel PRACH. When the medium accesscontrol (MAC) layer of a UE indicates PRACH transmission to the physicallayer of the UE, the physical layer of the UE selects one access slotand one signature and transmits a PRACH preamble on UL. The randomaccess procedure is contention-based or contention-free.

Referring to FIG. 2, a UE receives random access information in systeminformation from a BS and stores the random access information.Subsequently, when random access is required, the UE transmits a randomaccess preamble (message 1 or Msg1) to the BS (S21). The random accesspreamble may also be referred to as an RACH preamble or a PRACHpreamble. Upon receipt of the random access preamble from the UE, the BStransmits an RAR (message 2 or Msg2) to the UE (S22). Specifically, DLscheduling information for the RAR may be cyclic redundancy check(CRC)-masked with a random access RNTI (RA-RNTI) and transmitted on anL1/L2 control channel (PDCCH). Upon receipt of the DL scheduling signalmasked with the RA-RNTI, the UE may receive the RAR on a PDSCH anddecode the RAR. The UE then checks whether the RAR includes RARinformation directed to the UE. The UE may determine whether the RARincludes the random access preamble ID (RAID) of the transmittedpreamble to check whether the RAR includes RAR information directed tothe UE. The RAR includes a timing advance (TA) which is timing offsetinformation for synchronization, radio resource allocation informationfor UL, and a temporary ID (e.g., temporary cell RNTI (C-RNTI)) for UEidentification. Upon receipt of the RAR, the UE performs a ULtransmission (message 3 or Msg3) including an RRC Connection Requestmessage on a UL shared channel according to the radio resourceallocation information included in the RAR (S23). After receiving the ULtransmission from the UE, the BS transmits a message for contentionresolution (message 4 or Msg4) to the UE (S24). The message forcontention resolution may be referred to as a contention resolutionmessage and include an RRC Connection Setup message. After receiving thecontention resolution message from the BS, the UE completes theconnection setup and then transmits a Connection Setup Complete message(message 5 or Msg5) to the BS (S25).

In a contention-free random access (CFRA) procedure, before the UEtransmits the random access preamble (S21), the BS may allocate acontention-free random access preamble to the UE. The contention-freerandom access preamble may be allocated by a handover command ordedicated signaling such as a PDCCH. When the contention-free randomaccess preamble is allocated to the UE, the UE may transmit theallocated contention-free random access preamble to the BS in a similarmanner to in step S21. Upon receipt of the contention-free random accesspreamble from the UE, the BS may transmit an RAR to the UE in a similarmanner to in step S22.

Radio Frame Structures

FIG. 3 illustrates LTE radio frame structures. LTE supports frame type 1for frequency division duplex (FDD), frame type 2 for time divisionduplex (TDD), and frame type 3 for an unlicensed cell (UCell). Up to 31secondary cells (SCells) may be aggregated in addition to a primary cell(PCell). Unless otherwise specified, operations described in thedisclosure may be applied independently on a cell basis. In multi-cellaggregation, different frame structures may be used for different cells.Further, time resources (e.g., a subframe, a slot, and a subslot) withina frame structure may be generically referred to as a time unit (TU).

FIG. 3(a) illustrates frame type 1. A DL radio frame is defined by 101-ms subframes (SFs). A subframe includes 14 or 12 symbols according toa cyclic prefix (CP). In a normal CP case, a subframe includes 14symbols, and in an extended CP case, a subframe includes 12 symbols.Depending on multiple access schemes, a symbol may be an OFDM(A) symbolor an SC-FDM(A) symbol. For example, a symbol may refer to an OFDM(A)symbol on DL and an SC-FDM(A) symbol on UL. An OFDM(A) symbol may bereferred to as a cyclic prefix-OFDMA(A) (CP-OFDM(A)) symbol, and anSC-FMD(A) symbol may be referred to as a discrete Fouriertransform-spread-OFDM(A) (DFT-s-OFDM(A)) symbol.

FIG. 3(b) illustrates frame type 2. Frame type 2 includes two halfframes. A half frame includes 4 (or 5) general subframes and 1 (or 0)special subframe. According to a UL-DL configuration, a general subframeis used for UL or DL. A subframe includes two slots.

The above-described radio frame structures are merely exemplary, and thenumber of subframes in a radio frame, the number of slots in a subframe,and the number of symbols in a slot may vary.

FIG. 4 is a diagram illustrating a slot structure in an LTE frame.

Referring to FIG. 4, a slot includes a plurality of symbols in the timedomain by a plurality of resource blocks (RBs) in the frequency domain.A symbol may refer to a symbol duration. A slot structure may berepresented as a resource grid including N^(DL/UL) _(RBX)N^(RB) _(sc)subcarriers and N^(DL/UL) _(symb) symbols. N^(DL) _(RB) represents thenumber of RBs in a DL slot, and N^(UL) _(RB) represents the number ofRBs in a UL slot. N^(DL) _(RB) and N^(UL) _(RB) are dependent on a DLbandwidth and a UL bandwidth, respectively. N^(DL) _(symb) representsthe number of symbols in the DL slot, and N^(UL) _(symb) represents thenumber of symbols in the UL slot. N^(RB) _(sc) represents the number ofsubcarriers in one RB. The number of symbols in a slot may varyaccording to a subcarrier spacing (SCS) and a CP length. For example,one slot includes 7 symbols in the normal CP case, whereas one slotincludes 6 symbols in the extended CP case.

An RB is defined as N^(DL/UL) _(symb) (e.g., 7) consecutive symbols inthe time domain by N^(RB) _(sc) (e.g., 12) consecutive subcarriers inthe frequency domain. The RB may be a physical resource block (PRB) or avirtual resource block (VRB), and PRBs may be mapped to VRBs in aone-to-one correspondence. Two RBs each being located in one of the twoslots of a subframe may be referred to as an RB pair. The two RBs of anRB pair may have the same RB number (or RB index). A resource includingone symbol by one subcarrier is referred to as a resource element (RE)or tone. Each RE of a resource grid may be uniquely identified by anindex pair (k, 1) in a slot where k is a frequency-domain index rangingfrom 0 to N^(DL/UL) _(RBX)N^(RB) _(sc)−1 and 1 is a time-domain indexranging from 0 to N^(DL/UL) _(symb)−1.

Up to three (or four) OFDM(A) symbols at the beginning of the first slotof a subframe correspond to a control region. The remaining OFDM(A)symbols correspond to a data region in which a PDSCH is allocated, and abasic resource unit of the data region is an RB. DL control channelsinclude physical control format indicator channel (PCFICH), PDCCH,physical hybrid-ARQ indicator channel (PHICH), and so on. The PCFICH istransmitted in the first OFDM symbol of a subframe, conveyinginformation about the number of OFDM symbols used for transmission ofcontrol channels in the subframe. The PHICH is a response to a ULtransmission, conveying an HARQ ACK/NACK signal. Control informationdelivered on the PDCCH is called downlink control information (DCI). TheDCI includes UL resource allocation information, DL resource controlinformation, or a UL transmit power control command for any UE group.

A subframe includes two 0.5-ms slots. Each slot includes a plurality ofsymbols, each corresponding to one SC-FDMA symbol. An RB is a resourceallocation unit corresponding to 12 subcarriers in the frequency domainby one slot in the time domain. An LTE UL subframe is divided largelyinto a control region and a data region. The data region iscommunication resources used for each UE to transmit data such as voice,packets, and so on, including a PUSCH. The control region iscommunication resources used for each UE to transmit a DL channelquality report, an ACK/NACK for a DL signal, a UL scheduling request,and so on, including a PUCCH. A sounding reference signal (SRS) istransmitted in the last SC-FDMA symbol of a subframe in the time domain.

FIG. 5 illustrates a radio frame structure used in an NR system.

In NR, UL and DL transmissions are configured in frames. Each radioframe has a length of 10 ms and is divided into two 5-ms half frames(HFs). Each half frame is divided into five 1-ms subframes. A subframeis divided into one or more slots, and the number of slots in a subframedepends on an SCS. Each slot includes 12 or 14 OFDM(A) symbols accordingto a CP. When a normal CP is used, each slot includes 14 OFDM symbols.When an extended CP is used, each slot includes 12 OFDM symbols. Asymbol may include an OFDM symbol (CP-OFDM symbol) and an SC-FDMA symbol(or DFT-s-OFDM symbol).

Table 1 exemplarily illustrates that the number of symbols per slot, thenumber of slots per frame, and the number of slots per subframe varyaccording to SCSs in the normal CP case.

TABLE 1 SCS (15 × 2^(μ)) N_(symb) ^(slot) N_(slot) ^(frame,μ) N_(slot)^(subframe,μ)  15 KHz (μ = 0) 14  10  1  30 KHz (μ = 1) 14  20  2  60KHz (μ = 2) 14  40  4 120 KHz (μ = 3) 14  80  8 240 KHz (μ = 4) 14 16016 * N_(symb) ^(slot): number of symbols in a slot * N_(slot)^(frame,μ): number of slots in a frame * N_(slot) ^(subframe,μ): numberof slots in a subframe

Table 2 illustrates that the number of symbols per slot, the number ofslots per frame, and the number of slots per subframe vary according toSCSs in the extended CP case.

TABLE 2 SCS (15 × 2^(μ)) N_(symb) ^(slot) N_(slot) ^(frame,μ) N_(slot)^(subframe,μ) 60 KHz (μ = 2) 12 40 4

In the NR system, different OFDM(A) numerologies (e.g., SCSs, CPlengths, and so on) may be configured for a plurality of cellsaggregated for one UE. Accordingly, the (absolute time) duration of atime resource (e.g., a subframe, a slot, or a transmission time interval(TTI)) (for convenience, referred to as a TU) including the same numberof symbols may be configured differently for the aggregated cells.

FIG. 6 illustrates a slot structure of an NR frame.

A slot includes a plurality of symbols in the time domain. For example,one slot includes 14 symbols in the normal CP case and 12 symbols in theextended CP case. A carrier includes a plurality of subcarriers in thefrequency domain. An RB may be defined by a plurality of (e.g., 12)consecutive subcarriers in the frequency domain. A bandwidth part (BWP)may be defined by a plurality of consecutive (P)RBs in the frequencydomain and correspond to one numerology (e.g., SCS, CP length, and soon). A carrier may include up to N (e.g., 5) BWPs. Data communicationmay be conducted in an active BWP, and only one BWP may be activated forone UE. Each element of a resource grid may be referred to as an RE, towhich one complex symbol may be mapped.

B. UL and DL Channels

DL Channels

A BS transmits related signals on DL channels to a UE, and the UEreceives the related signals on the DL channels from the BS.

(1) Physical Downlink Shared Channel (PDSCH)

The PDSCH delivers DL data (e.g., a DL shared channel transport block(DL-SCH TB)) and adopts a modulation scheme such as quadrature phaseshift keying (QPSK), 16-ary quadrature amplitude modulation (16 QAM),64-ary QAM (64 QAM), or 256-ary QAM (256 QAM). A TB is encoded to acodeword. The PDSCH may deliver up to two codewords. The codewords areindividually subjected to scrambling and modulation mapping, andmodulation symbols from each codeword are mapped to one or more layers.An OFDM signal is generated by mapping each layer together with ademodulation reference signal (DMRS) to resources, and transmittedthrough a corresponding antenna port.

(2) Physical Downlink Control Channel (PDCCH)

The PDCCH delivers DCI and adopts QPSK as a modulation scheme. One PDCCHincludes 1, 2, 4, 8, or 16 control channel elements (CCEs) according toits aggregation level (AL). One CCE includes 6 resource element groups(REGs), each REG being defined by one OFDM symbol by one (P)RB. ThePDCCH is transmitted in a control resource set (CORESET). A CORESET isdefined as a set of REGs with a given numerology (e.g., an SCS, a CPlength, or the like). A plurality of CORESETs for one UE may overlapwith each other in the time/frequency domain. A CORESET may beconfigured by system information (e.g., a master information block(MIB)) or UE-specific higher-layer signaling (e.g., RRC signaling).Specifically, the number of RBs and the number of symbols (3 at maximum)in the CORESET may be configured by higher-layer signaling.

The UE acquires DCI delivered on the PDCCH by decoding (so-called blinddecoding) a set of PDCCH candidates. A set of PDCCH candidates decodedby a UE are defined as a PDCCH search space set. A search space set maybe a common search space (CSS) or a UE-specific search space (USS). TheUE may acquire DCI by monitoring PDCCH candidates in one or more searchspace sets configured by an MIB or higher-layer signaling. Each CORESETconfiguration is associated with one or more search space sets, and eachsearch space set is associated with one CORESET configuration. Onesearch space set is determined based on the following parameters.

-   -   controlResourceSetID: A set of control resources related to the        search space set.

monitoringSlotPeriodiciAndOffset: A PDCCH monitoring periodicity (inslots) and a PDCCH monitoring offset (in slots).

monitoringSymbolsWithinSlot: A PDCCH monitoring pattern (e.g., the firstsymbol(s) in a CORESET) in a PDCCH monitoring slot.

nrofCandidates: The number of PDCCH candidates (one of 0, 1, 2, 3, 4, 5,6, and 8) for each AL={1, 2, 4, 8, 16}.

Table 3 lists exemplary features of each search space type.

TABLE 3 Search Type Space RNTI Use Case Type0-PDCCH Common SI-RNTI on aprimary cell SIB Decoding Type0A-PDCCH Common SI-RNTI on a primary cellSIB Decoding Type1-PDCCH Common RA-RNTI or TC-RNTI Msg2, Msg4 on aprimary cell decoding in RACH Type2-PDCCH Common P-RNTI on a primarycell Paging Decoding Type3-PDCCH Common INT-RNTI, SFI-RNTI,TPC-PUSCH-RNTI, TPC-PUCCH-RNTI, TPC-SRS-RNTI, C-RNTI, MCS-C-RNTI, orCS-RNTI (s) UE C-RNTI, or MCS-C-RNTI, User specific Specific or CS-RNTI(s) PDSCH decoding

Table 4 lists exemplary DCI formats transmitted on the PDCCH.

TABLE 4 DCI format Usage 0_0 Scheduling of PUSCH in one cell 0_1Scheduling of PUSCH in one cell 1_0 Scheduling of PDSCH in one cell 1_1Scheduling of PDSCH in one cell 2_0 Notifying a group of UEs of the slotformat 2_1 Notifying a group of UEs of the PRB (s) and OFDM symbol (s)where UE may assume no transmission is intended for the UE 2_2Transmission of TPC commands for PUCCH and PUSCH 2_3 Transmission of agroup of TPC commands for SRS transmissions by one or more UEs

DCI format 0_0 may be used to schedule a TB-based (or TB-level) PUSCH,and DCI format 0_1 may be used to schedule a TB-based (or TB-level)PUSCH or a code block group (CBG)-based (or CBG-level) PUSCH. DCI format1_0 may be used to schedule a TB-based (or TB-level) PDSCH, and DCIformat 1_1 may be used to schedule a TB-based (or TB-level) PDSCH or aCBG-based (or CBG-level) PDSCH. DCI format 2_0 is used to deliverdynamic slot format information (e.g., a dynamic slot format indicator(SFI)) to a UE, and DCI format 2_1 is used to deliver DL preemptioninformation to a UE. DCI format 2_0 and/or DCI format 2_1 may bedelivered to a corresponding group of UEs on a group common PDCCH whichis a PDCCH directed to a group of UEs.

UL Channels

A UE transmits related signals on UL channels to a BS, and the BSreceives the related signals on the UL channels from the UE.

(1) Physical Uplink Shared Channel (PUSCH)

The PUSCH delivers UL data (e.g., UL shared channel transport block(UL-SCH TB)) and/or UCI based on a CP-OFDM waveform or a DFT-s-OFDMwaveform. When the PUSCH is transmitted in the DFT-s-OFDM waveform, theUE transmits the PUSCH by transform precoding. For example, whentransform precoding is impossible (e.g., disabled), the UE may transmitthe PUSCH in the CP-OFDM waveform, while when transform precoding ispossible (e.g., enabled), the UE may transmit the PUSCH in the CP-OFDMor DFT-s-OFDM waveform. A PUSCH transmission may be scheduleddynamically by a UL grant in DCI, or semi-statically by higher-layersignaling (e.g., RRC signaling) (and/or layer 1 (L1) signaling such as aPDCCH) (configured grant). The PUSCH transmission may be performed in acodebook-based or non-codebook-based manner.

(2) Physical Uplink Control Channel (PUCCH)

The PUCCH delivers UCI, an HARQ ACK, and/or an SR and is classified as ashort PUCCH or a long PUCCH according to the transmission duration ofthe PUCCH. Table 5 lists exemplary PUCCH formats.

TABLE 5 Length in OFDM Number PUCCH symbols of format N_(symb) ^(PUCCI)bits Usage Etc 0 1-2 ≤2 HARQ, SR Sequence selection 1  4-14 ≤2 HARQ,[SR] Sequence modulation 2 1-2 >2 HARQ, CSI, [SR] CP-OFDM 3  4-14 >2HARQ, CSI, [SR] DFT-s-OFDM (no UE multiplexing) 4  4-14 >2 HARQ, CSI,[SR] DFT-s-OFDM (Pre DFT OCC)

C. Machine Type Communication (MTC)

MTC, which is a type of data communication involving one or moremachines, may be applied to machine-to-machine (M2M) or Internet ofthings (IoT). A machine refers to an entity that does not require directhuman manipulation or intervention. For example, machines include asmart meter equipped with a mobile communication module, a vendingmachine, a portable terminal having an MTC function, and so on. Forexample, services such as meter reading, water level measurement, use ofsurveillance cameras, and inventory reporting of vending machines may beprovided through MTC. MTC has the features of a small amount oftransmission data and intermittent UL/DL data transmissions/receptions.Therefore, it is efficient to lower the unit cost of MTC devices andreduce battery consumption in correspondence with low data rates. An MTCdevice generally has low mobility, and thus MTC is conducted in achannel environment which hardly changes.

The 3GPP has applied MTC since release 10, and MTC may be implemented tosatisfy the requirements of low cost and low complexity, coverageenhancement, and low power consumption. For example, 3GPP Release 12added features for low-cost MTC devices and thus defined UE category 0.A UE category is an indicator indicating the amount of data that a UEmay process in a communication modem. A UE of UE category 0 may reducebaseband/radio frequency (RF) complexity by using a reduced peak datarate, a half-duplex operation with relaxed RF requirements, and a singlereception (Rx) antenna. In 3GPP Release 12, enhanced MTC (eMTC) wasintroduced, and the price and power consumption of MTC UEs were furtherlowered by operating the MTC UEs only at 1.08 MHz (that is, 6 RBs), aminimum frequency bandwidth supported in legacy LTE.

While the present disclosure is described mainly in the context offeatures related to eMTC, the present disclosure is equally applicableto MTC, eMTC, and MTC applied to 5G (or NR) unless otherwise specified.For the convenience of description, MTC, eMTC, and MTC applied to 5G (orNR) are generically referred to as MTC herein.

FIG. 7 illustrates cell coverage enhancement in MTC. Coverageenhancement may also be expressed as coverage extension, and a techniquefor coverage enhancement described in relation to MTC may be applied toNB-IoT and 5G (or NR) in the same/similar manner.

For cell extension or cell enhancement (CE) of a BS 1204 to an MTCdevice 1202, various CE techniques are under discussion. For example,for CE, the BS/UE may transmit/receive one physical channel/signal in aplurality of occasions (a bundle of physical channels). The physicalchannel/signal may be repeatedly transmitted/received according to apredefined rule during a bundle interval. A receiver may increase thedecoding success rate of the physical channel/signal by decoding some orall of the physical channel/signal bundle. An occasion may meanresources (e.g., time/frequency) in which a physical channel/signal maybe transmitted/received. An occasion for a physical channel/signal mayinclude a subframe, a slot, or a symbol set in the time domain. Thesymbol set may include one or more consecutive OFDM-based symbols. AnOFDM-based symbol may include an OFDM(A) symbol and a DFT-s-OFDM(A)(i.e., SC-FDM(A)) symbol. The occasion for a physical channel/signal mayinclude a frequency band or an RB set in the frequency domain. Forexample, a PBCH, a PRACH, an MTC PDCCH (MPDCCH), a PDSCH, a PUCCH, and aPUSCH may be repeatedly transmitted/received.

MTC supports an operation mode for CE, and a mode supporting repeatedtransmissions/receptions of a signal for CE may be referred to as a CEmode. The number of repeated transmissions/receptions of a signal for CEmay be referred to as a CE level. Table 6 illustrates exemplary CEmodes/levels supported in MTC.

TABLE 6 Mode Level Description Mode A Level 1 No repetition for PRACHLevel 2 Small Number of Repetition for PRACH Mode B Level 3 MediumNumber of Repetition for PRACH Level 4 Large Number of Repetition forPRACH

A first mode (e.g., CE Mode A) is defined for small CE, supporting fullmobility and CSI feedback, in which no repetition or a small number ofrepetitions are performed. A first-mode operation may be identical tothe operation range of UE category 1. A second mode (e.g., CE Mode B) isdefined for UEs in an extremely poor coverage condition, supporting CSIfeedback and limited mobility, in which a large number of repeatedtransmissions are defined. The second mode provides up to 15 dB of CEwith respect to the range of UE category 1. Each level of MTC is defineddifferently for a random access procedure (or RACH procedure) and apaging procedure.

FIG. 8 illustrates MTC signal bands.

Referring to FIG. 8, to reduce the unit cost of MTC UEs, MTC may beconducted only in a specific band (or channel band) (MTC subband ornarrowband (NB)) of the system bandwidth of a cell, regardless of thesystem bandwidth of the cell. For example, an MTC UE may perform a UL/DLoperation only in a 1.08-MHz frequency band. 1.0 MHz corresponds to sixconsecutive PRBs in the LTE system, and is defined to enable MTC UEs tofollow the same cell search and random access procedures as LTE UEs.FIG. 8(a) illustrates an MTC subband configured at the center of a cell(e.g., center 6 PRBs), and FIG. 8(b) illustrates a plurality of MTCsubbands configured within a cell. The plurality of MTC subbands may beconfigured contiguously/non-contiguously in the frequency domain.Physical channels/signals for MTC may be transmitted and received in oneMTC subband. In the NR system, an MTC subband may be defined inconsideration of a frequency range and an SCS. In the NR system, forexample, the size of an MTC subband may be defined as X consecutive PRBs(i.e., 0.18*X*(2{circumflex over ( )}μ)MHz bandwidth) (see Table 1 forμ). X may be set to 20 according to the size of a synchronizationsignal/physical broadcast channel (SS/PBCH) block. In the NR system, MTCmay operate in at least one BWP. A plurality of MTC subbands may beconfigured in a BWP.

FIG. 9 illustrates scheduling in legacy LTE and MTC.

Referring to FIG. 9, a PDSCH is scheduled by a PDCCH in legacy LTE.Specifically, the PDCCH may be transmitted in the first N OFDM symbolsin a subframe (N=1 to 3), and the PDSCH scheduled by the PDCCH istransmitted in the same subframe. In MTC, a PDSCH is scheduled by anMPDCCH. Accordingly, an MTC UE may monitor MPDCCH candidates in a searchspace within a subframe. The monitoring includes blind decoding of theMPDCCH candidates. The MPDCCH delivers DCI, and the DCI includes UL orDL scheduling information. The MPDCCH is multiplexed with the PDSCH inFDM in a subframe. The MPDCCH is repeatedly transmitted in up to 256subframes, and the DCI carried in the MPDCCH includes information aboutan MPDCCH repetition number. In DL scheduling, when the repeatedtransmissions of the MPDCCH end in subframe #N, transmission of thePDSCH scheduled by the MPDCCH starts in subframe #N+2. The PDSCH may berepeatedly transmitted in up to 2048 subframes. The MPDCCH and the PDSCHmay be transmitted in different MTC subbands. In UL scheduling, when therepeated transmissions of the MPDCCH end in subframe #N, transmission ofa PUSCH scheduled by the MPDCCH starts in subframe #N+4. For example,when the PDSCH is repeatedly transmitted in 32 subframes, the PDSCH maybe transmitted in the first 16 subframes in a first MTC subband, and inthe remaining 16 subframes in a second MTC subband. MTC operates in ahalf-duplex mode. MTC HARQ retransmission is adaptive and asynchronous.

D. Narrowband Internet of Things (NB-IoT)

NB-IoT is a narrowband Internet of things technology supporting alow-power wide area network through an existing wireless communicationsystem (e.g., LTE or NR). Further, NB-IoT may refer to a systemsupporting low complexity and low power consumption in a narrowband(NB). Since an NB-IoT system uses the same OFDM parameters as those ofan existing system, such as an SCS, there is no need to allocate anadditional band separately for the NB-IoT system. For example, one PRBof an existing system band may be allocated for NB-IoT. Considering thatan NB-IoT UE perceives a single PRB as a carrier, PRB and carrier may beinterpreted as the same meaning in the description of NB-IoT.

NB-IoT may operate in a multi-carrier mode. In NB-IoT, a carrier may bedefined as an anchor type carrier (i.e., anchor carrier or anchor PRB)or a non-anchor type carrier (i.e., non-anchor carrier or non-anchorPRB). From the perspective of a BS, the anchor carrier may mean acarrier carrying a narrowband PSS (NPSS), a narrowband SSS (NSSS), and anarrowband PBCH (NPBCH) for initial access, and a narrowband PDSCH(NPDSCH) for a narrowband system information block (N-SIB). That is, inNB-IoT, a carrier for initial access may be referred to as an anchorcarrier, and the other carrier(s) may be referred to as non-anchorcarrier(s). One or more anchor carriers may exist in the system.

While NB-IoT is described mainly in the context of being applied to thelegacy LTE system in the present disclosure, the description may beextended to a next-generation system (e.g., NR system). In the presentdisclosure, the description of NB-IoT may be extended to MTC serving asimilar technical purpose (e.g., low-power, low-cost, and CE). The termNB-IoT may be replaced with other equivalent terms such as NB-LTE,NB-IoT enhancement, enhanced NB-IoT, further enhanced NB-IoT, and NB-NR.

NB-IoT DL physical channels include NPBCH, NPDSCH, and NPDCCH, andNB-IoT DL physical signals include NPSS, NSSS, and narrowband RS (NRS).

A different NB-IoT frame structure may be configured according to anSCS. For example, the NB-IoT system may support a 15 kHz SCS and a 3.75kHz SCS. NB-IoT may be considered for any other SCS (e.g., 30 kHz) withdifferent time/frequency units, not limited to the 15 kHz SCS and the3.75 kHz SCS. While the NB-IoT frame structure based on the LTE systemframe structure has been described herein for the convenience ofdescription, the present disclosure is not limited thereto. Obviously,methods described in the present disclosure may be extended to NB-IoTbased on a frame structure of the next-generation system (e.g., NRsystem).

An NB-IoT frame structure for the 15 kHz SCS may be configured to beidentical to the frame structure of the above-described legacy system(i.e., LTE system). That is, a 10-ms NB-IoT frame may include 10 1-msNB-IoT subframes, each including two 0.5-ms NB-IoT slots. Each 0.5-msNB-IoT slot may include 7 OFDM symbols.

For the 3.75 kHz SCS, a 10-ms NB-IoT frame includes 5 2-ms NB-IoTsubframes, each including 7 OFDM symbols and one guard period (GP). A2-ms NB-IoT subframe may also be referred to as an NB-IoT slot or anNB-IoT resource unit (RU).

NB-IoT DL physical resources may be configured based on theconfiguration of physical resources in another wireless communicationsystem (e.g., LTE or NR), except that an NR system bandwidth is acertain number of RBs (e.g., one RB, i.e., 180 kHz). For example, whenthe NB-IoT DL supports only the 15 kHz SCS, the NB-IoT DL physicalresources may be configured as the resource area of one RB (i.e., onePRB) in the frequency domain, to which the resource grid of the LTEsystem illustrated in FIG. 4 is limited, as described above. Likewise,for NB-IoT UL physical resources, the system bandwidth may be limited toone RB.

FIG. 10 illustrates transmission of NB-IoT DL physical channels/signals.An NB-IoT DL physical channel/signal is transmitted in one PRB andsupports the 15 kHz SCS/multi-tone transmission.

Referring to FIG. 10, the NPSS is transmitted in the sixth subframe ofevery frame, and the NSSS is transmitted in the last (e.g., tenth)subframe of every even-numbered frame. A UE may acquire frequency,symbol, and frame synchronization using the synchronization signals(NPSS and NSSS) and search 504 physical cell IDs (PCIDs) (i.e., BS IDs).The NPBCH is transmitted in the first subframe of every frame, carryingan NB-MIB. The NRS is provided as an RS for DL physical channeldemodulation and generated in the same manner as in LTE. However, anNB-PCID (NCell ID or NB-IoT BS ID) is used as an initialization valuefor generation of an NRS sequence. The NRS is transmitted through one ortwo antenna ports. The NPDCCH and the NPDSCH may be transmitted in theremaining subframes except for the subframes carrying the NPSS, theNSSS, and the NPBCH. The NPDCCH and the NPDSCH may not be transmitted inthe same subframe. The NPDCCH carries DCI, and the DCI supports threetypes of DCI formats. DCI format NO includes NPUSCH schedulinginformation, and DCI formats N1 and N2 include NPDSCH schedulinginformation. The NPDCCH may be transmitted up to 2048 times, for CE. TheNPDSCH is used to transmit data (e.g., TB) of a transport channel suchas a DL-SCH and a paging channel (PCH). A maximum TB size (TBS) is 680bits, and a TB may be repeatedly transmitted up to 2048 times, for CE.

NB-IoT UL physical channels include narrowband PRACH (NPRACH) andNPUSCH, and support single-tone transmission and multi-tonetransmission. Single-tone transmission is supported for the SCSs of 3.5kHz and 15 kHz, and multi-tone transmission is supported only for the 15kHz SCS.

SC-FDMA may be applied to NB-IoT UL based on the SCS of 15 kHz or 3.75kHz. Multi-tone transmission and single-tone transmission may besupported for the NB-IoT UL. For example, multi-tone transmission issupported only for the 15 kHz SCS, and single-tone transmission may besupported for the SCSs of 15 kHz and 3.75 kHz.

As mentioned in relation to the NB-IoT DL, the physical channels of theNB-IoT system may have names added with “N (Narrowband)” to distinguishthem from the channels of the existing systems. For example, the NB-IoTUL physical channels may include NPRACH, NPUSCH, and so on, and theNB-IoT UL physical signals may include narrowband DMRS (NDMRS).

The NPUSCH may be configured in NPUSCH format 1 or NPUSCH format 2. Forexample, NPUSCH format 1 may be used to carry (or deliver) a UL-SCH, andNPUSCH format 2 may be used to transmit UCI such as an HARQ ACK.

Characteristically, the UL channel of the NB-IoT system, NPRACH may berepeatedly transmitted, for CE. In this case, frequency hopping may beapplied to the repeated transmissions.

E. Network Access and Communication Procedure

A UE may perform a network access procedure to perform the proceduresand/or methods described/proposed in the present disclosure. Forexample, the UE may receive system information and configurationinformation required to perform the described/proposed procedures and/ormethods and store the received information in a memory, during network(BS) access. The configuration information required for the presentdisclosure may be received by higher-layer signaling (e.g., RRC layersignaling, MAC-layer signaling, or the like).

FIG. 11 is a diagram illustrating a signal flow for an initial networkaccess procedure and a subsequent communication procedure in the NRsystem. In NR, a physical channel and an RS may be transmitted bybeamforming. When beamforming-based signal transmission is supported, abeam management process may be involved to align beams between a BS anda UE. Further, signals proposed in the present disclosure may betransmitted/received by beamforming. In RRC idle mode, beam alignmentmay be performed based on an SSB, whereas in RRC connected mode, beamalignment may be performed based on a CSI-RS (in DL) and an SRS (in UL).On the contrary, when beamforming-based signal transmission is notsupported, an operation related to a beam may be skipped in thedescription of the present disclosure.

Referring to FIG. 11, a BS may periodically transmit an SSB (S1902). TheSSB includes a PSS, an SSS, and a PBCH. The SSB may be transmitted bybeam sweeping. The PBCH includes an MIB, and the MIB may includescheduling information for remaining minimum system information (RMSI).Subsequently, the BS may transmit the RMSI and other system information(OSI) (S1904). The RMSI may include information (e.g., PRACHconfiguration information) required for a UE to initially access the BS.After detecting SSBs, the UE identifies the best SSB. The UE may thentransmit an RACH preamble (message 1 or Msg1) to the BS in PRACHresources linked/corresponding to the index (i.e., beam) of the best SSB(S1906). The beam direction of the RACH preamble is associated with thePRACH resources. The association between the PRACH resources (and/or theRACH preamble) and the SSB (index) may be configured by systeminformation (e.g., RMSI). As part of the random access procedure (orRACH procedure), the BS may transmit an RAR (Msg2) in response to theRACH preamble (S1908). The UE may transmit Msg3 (e.g., RRC ConnectionRequest) based on a UL grant included in the RAR (S1910), and the BS maytransmit a contention resolution message (Msg4) (S1920). Msg4 mayinclude an RRC Connection Setup message.

When an RRC connection is established between the BS and the UE in therandom access procedure (or RACH procedure), a subsequent beam alignmentmay be performed based on an SSB/CSI-RS (in DL) and an SRS (in UL). Forexample, the UE may receive an SSB/CSI-RS (S1914). The SSB/CSI-RS may beused for the UE to generate a beam/CSI report. The BS may request abeam/CSI report to the UE by DCI (S1916). In this case, the UE maygenerate a beam/CSI report based on the SSB/CSI-RS, and transmit thegenerated beam/CSI report to the BS on a PUSCH/PUCCH (S1918). Thebeam/CSI report may include a beam measurement result, information abouta preferred beam, and so on. The BS and the UE may switch a beam basedon the beam/CSI report (S1920 a and S1920b).

Subsequently, the UE and the BS may perform the above-described/proposedprocedures and/or methods. For example, the UE and the BS may processinformation stored in the memory and transmit a radio signal or processa received radio signal and store the processed signal in the memoryaccording to a proposal of the present disclosure, based on theconfiguration information obtained in the network access procedure(e.g., the system information acquisition procedure, the RRC connectionprocedure through an RACH, and so on). The radio signal may include atleast one of a PDCCH, a PDSCH, or an RS for DL, and at least one of aPUCCH, a PUSCH, or an SRS for UL.

Basically, the above description may be applied commonly to MTC andNB-IoT. The difference between MTC and NB-IoT will further be describedbelow.

MTC Network Access Procedure

An MTC network access procedure will be further described in the contextof LTE. The following description may be extended to NR as well. In FIG.1 and/or FIG. 11, a PDCCH is replaced by an MPDCCH (e.g., see FIG. 9 andthe related description).

In LTE, an MIB includes 10 reserved bits. In MTC, 5 most significantbits (MSBs) out of the 10 reserved bits of the MIB are used to indicatescheduling information for system information block for bandwidthreduced device (SIB1-BR). The 5 MSBs are used to indicate the repetitionnumber and TBS of the SIB1-BR. The SIB1-BR is transmitted on a PDSCH.The SIB1-BR may be kept unchanged in 512 radio frames (5120 ms) to allowcombining of multiple subframes. The SIB1-BR delivers similarinformation to that of SIB1 in LTE.

An MTC random access procedure (or RACH procedure) is basicallyidentical to the LTE random access procedure (or RACH procedure) (e.g.,see FIG. 2 and the related description), except that the former isperformed based on a CE level. For example, whether the PRACH isrepeatedly transmitted and/or the repetition number of the PRACH mayvary with CE levels, for PRACH CE. As described with reference to Table6, a mode supporting repeated transmissions of a signal for CE isreferred to as a CE mode, and the repetition number of the signal for CEis referred to as a CE level. For example, as illustrated in Table 6,the first mode (e.g., CE Mode A) is a mode for small CE supporting fullmobility and CSI feedback, in which no repetition or a small number ofrepetitions may be set. The second mode (e.g., CE Mode B) is a mode fora UE in an extremely poor coverage condition, supporting CSI feedbackand limited mobility, in which a large repetition number may be set.

The BS broadcasts system information including a plurality of (e.g.,three) reference signal received power (RSRP) thresholds, and the UE maydetermine a CE level by comparing the RSRP thresholds with an RSRPmeasurement. The following information may be independently configuredon a CE level basis by system information.

PRACH resource information: the periodicity/offset of PRACH occasions,and PRACH frequency resources

Preamble Group: Preamble set allocated for each CE level

Repetition number per preamble attempt and maximum number of preambleattempts

RAR window time: the length of a time period during which RAR receptionis expected (e.g., in subframes)

Contention resolution window time: the length of a time period duringwhich a contention resolution message is expected to be received

The UE may select PRACH resources corresponding to its CE level and thenperform a PRACH transmission in the selected PRACH resources. A PRACHwaveform used in MTC is identical to a PRACH waveform used in LTE (e.g.,OFDM and Zadoff-Chu sequence). Signals/messages transmitted after thePRACH may also be repeatedly transmitted, and their repetition numbersmay be independently set according to CE modes/levels.

NB-IoT Network Access Procedure

A NB-IoT network access procedure will be further described in thecontext of LTE. The following description may be extended to NR as well.In FIGS. 1 and 11, PSS, SSS, and PBCH are replaced with NPSS, NSSS, andNPBCH in NB-IoT, respectively. For details of the NPSS, the NSSS and theNPBCH, refer to FIG. 10. Further, PDCCH, PDSCH, PUSCH, and PRACH arereplaced with NPDCCH, NPDSCH, NPUSCH, and NPRACH, respectively in FIG. 1and/or FIG. 11.

The NB-IoT random access procedure (or RACH procedure) is basicallyidentical to the LTE random access procedure (or RACH procedure) (e.g.,see FIG. 2 and the related description), differing in the following.First, RACH preamble formats are different. In LTE, a preamble is basedon a code/sequence (e.g., Zadoff-Chu sequence), whereas in NB-IoT, apreamble is a subcarrier. Second, the NB-IoT random access procedure (orRACH procedure) is performed based on a CE level. Therefore, differentPRACH resources are allocated for different CE levels. Third, since SRresource are not configured in NB-IoT, a UL resource allocation requestis transmitted in the random access process (or RACH procedure) inNB-IoT.

FIG. 12 illustrates preamble transmission on the NB-IoT RACH.

Referring to FIG. 12, an NPRACH preamble includes four symbol groups,each including a CP and a plurality of (e.g., 5) SC-FDMA symbols. In NR,SC-FDMA symbol may be replaced with OFDM symbol or DFT-s-OFDM symbol.For the NPRACH, only single-tone transmission with the 3.75 kHz SCS issupported, and CPs of 66.7 μs and 266.67 μs in length are provided tosupport different cell radii. Frequency hopping takes place in eachsymbol group, in the following hopping pattern. Subcarriers carrying thefirst symbol group are determined pseudo-randomly. 1-subcarrier hop,6-subcarrier hop, and 1-subcarrier hop take place respectively in thesecond, third, and fourth symbol groups. In the case of repeatedtransmissions, the frequency hopping procedure is repeatedly applied,and the NPRACH preamble may be repeatedly transmitted {1, 2, 4, 8, 16,32, 64, 128} times, for CE. NPRACH resources may be configured on a CElevel basis. The UE may select NPRACH resources based on a CE leveldetermined according to a DL measurement result (e.g., RSRP), andtransmit the RACH preamble in the selected NPRACH resources. The NPRACHmay be transmitted on an anchor carrier, or a non-anchor carrierconfigured with the NPRACH resources.

F. Proposed Methods of the Present Disclosure

The present disclosure makes proposals in relation to a procedure ofreporting a DL signal/channel quality in a random access procedure.

In general, a UE does not measure a channel quality in a random accessprocedure (or when DCI triggers CFRA in the RRC_CONNECTED state, CQIreporting in Msg3 may be indicated). Therefore, a BS performs DLscheduling in a conservative manner until before an RRC connection isestablished. A system supporting CE (e.g., MTC and NB-IoT) or anon-bandwidth reduced and low complexity (non-BL) UE (or legacy LTE UE)supporting a CE mode is characterized by repeated transmissions, andthus conservative DL scheduling even in the random access procedure mayresult in waste of too much resources.

In view of its nature (main services being metering and reporting), asystem such as MTC and NB-IoT is expected to be inoperative for long inthe RRC connected mode (or RRC_CONNECTED state). Accordingly, reportingdownlink (channel) quality information (DQI) as early as possible beforethe RRC connected mode may be favorable to the network and the UE interms of resource use efficiency and power saving. In this context, thepresent disclosure proposes an early DQI reporting method forefficiently helping with DL scheduling of a BS in a random accessprocedure. To minimize modifications to the legacy random accessprocedure, the present disclosure relates to a method and procedure fora network to provide, through system information and the Msg2 step,information which is required for a CQI report in Msg3.

Considering that the present disclosure will bring the greatest effectto a system characterized by repeated transmissions such as NB-IoT andMTC (or a BL/CE UE and a CE-mode UE), the present disclosure will bedescribed in the context of NB-IoT and MTC, for convenience. That is,proposed techniques of the present disclosure may also be applied to asystem in which repeated transmissions are not performed or a generalcommunication system. Besides, when the proposed methods are operativelyalmost the same between NB-IoT and MTC, the present disclosure isdescribed mainly in the context of NB-IoT, for convenience. However, thepresent disclosure is also applicable to a UE requiring a reducedbandwidth, low complexity, or CE (e.g., an MTC UE or a BL/CE UE) and arelated system, not limited to NB-IoT.

The above descriptions (of the 3GPP system, the frame structures, theMTC/NB-IoT system, and so on) may be applied in combination with theproposed methods of the present disclosure described below or used toclarify the technical features of the proposed methods of the presentdisclosure.

Abbreviations

ACK/NACK: Acknowledgement/Negative-Acknowledgement

AL: Aggregation Level

BER: Bit Error Rate

BLER: Block Error Rate

CE: Coverage Enhancement(or Coverage Extension)

BL/CE: Bandwidth reduced Low cost/Coverage Enhanced or Extended

CBRA: Contention Based Random Access

CCE: Control Channel Element

CE: Coverage Extension or Enhancement

CFRA: Contention Free Random Access

CQI: Channel Quality Information

CRS: Common or Cell-specific Reference Signal

CSI: Channel State Information

CSS: Common Search Space

DCA: Downlink Control Information

DMRS: DeModulation Reference Signal

DQI: Downlink (channel) Quality Information

DQI-RS: DQI-Reference reSource

ECCE: Enhanced Control Channel Element

EDT: Early Data Transmission

eMTC: enhanced Machine Type Communication

HARQ: Hybrid Automatic Repeat reQuest

MAC: Medium Access Control

MCS: Modulation and Coding Scheme

MTC: Machine Type Communication

NB: NarrowBand

NRS: Narrowband Reference Signal

PMI: Precoding Matrix indicator

PRB: Physical Resource Block

QAM: Quadrature Amplitude Modulation

R: Repetition number

RAR: Random Access Response

Preconfigured Uplink Resource

RB: Resource Block

RE: Resource Element

RI: Rank Indicator

RLM: Radio Link Monitoring

RRC: Radio Resource Control

RSRP: Reference Signal Received Power

RSRQ: Reference Signal Received Quality

RSSI: Received. Signal Strength Indicator

SIB: System Information Block

SNR: Signal-to-Noise Ratio

SPS: Semi-Persistent Scheduling

TA: Timing Advance

TBS: Transport Block Size

TM: Transmission Mode

UCI: Uplink Control Information

USS: UE-specific Search Space

Random Access Procedure

The random access procedure is generally performed in six steps.

(RA-0) A BS (e.g., eNB, gNB, network, or the like) broadcasts (ortransmits) information about resources to be used for random access.

The BS broadcasts a configuration of DL resources and UL resources usedfor a UE (e.g., terminal or the like) to the UE by system information(e.g., see step S12 of FIG. 1 or step S1904 of FIG. 11) during initialnetwork access. After acquiring DL synchronization, the UE checks arandom access-related configuration in the broadcast information fromthe BS and attempts to access by transmitting Msg1 (e.g., see step S13of FIG. 1 or step S1906 of FIG. 11). Msg1 may also be referred to as arandom access preamble, an RACH preamble, or a PRACH preamble.

In the MTC and NB-IoT systems, a different available Msg1time/frequency/sequence may be defined for the UE according to the CElevel of the UE. Besides, resources available in steps (RA-1), (RA-2),(RA-3), and (RA-4) may be configured differently for each CE level. TheCE level is determined according to a RSRP threshold broadcast in systeminformation by the BS, and the UE selects a CE level by comparing anRSRP value measured in DL by the UE with the RSRP threshold broadcast bythe BS. In MTC, CE modes are additionally defined, including CE Mode Aand CE Mode B (e.g., see Table 6 and the related description). Once theUE enters the RRC_CONNECTED state, the BS may configure a CE mode.However, the UE operates on the assumption of CE Mode A for CE levels 0and 1 and CE Mode B for CE levels 2 and 3 in the initial random accessprocedure.

(RA-1) The UE Transmits Msg1 to the BS.

The UE first determines its CE level and transmits the preamble (Msg1)(e.g., the random access preamble, the RACH preamble, or the PRACHpreamble) in Msg1 resources configured for the CE level (e.g., see stepS13 of FIG. 1 or step S1906 of FIG. 11). An RA-RNTI value is definedaccording to the time/frequency resources in which Msg1 is transmitted,and the Msg1 preamble selected by the UE is used as a random accesspreamble identifier (RAP-ID).

(RA-2) The BS Transmits a Response to the Detected Msg1 to the UE asMsg2.

Msg2 transmitted by the BS is referred to as a random access response(RAR), and the RAR is included in/transmitted through an (N)PDSCH. The(N)PDSCH is scheduled by an (N)PDCCH or an MPDCCH (e.g., see step S14 ofFIG. 1 or step S1908 of FIG. 11). Therefore, the UE monitors the(N)PDCCH or the MPDCCH after transmitting Msg1. Information required forattempting to detect the (N)PDCCH or the MPDCCH, such as informationabout time/frequency resources (e.g., an NB or an NB-IoT carrier),information about a maximum repetition number, and information aboutfrequency hopping, etc., is obtained from the information broadcast instep (RA-0). Since the (N)PDCCH or the MPDCCH that the UE attempts todetect has been scrambled with the RA-RNTI value in step (RA-1), UEswhich have transmitted Msg1 in the same time/frequency resources maydetect the same (N)PDCCH or MPDCCH ((N)PDCCH or MPDCCH scrambled withthe same RA-RNTI). When the UE successfully detects the (N)PDCCH orMPDCCH, the UE acquires RAR information by detecting an (N)PDSCHindicated by corresponding DCI. The RAR may include information about aplurality of Msg1s which are detected by the BS in step (RA-1), and theplurality of Msg1s are distinguished by RA-RNTIs. That is, the UEsearches, in the (N)PDSCH, the RA-RNTI value corresponding to the Msg1preamble that was used in step (RA-1), and acquires RAR informationcorresponding to the RA-RNTI. The RAR information includes aconfiguration for Msg3 to be transmitted in step (RA-3) by the UE and aTA value estimated in step (RA-1). The configuration for Msg3transmitted in step (RA-3) may be a UL grant. In MTC, the RAR alsoincludes information about the frequency resources (NB) of an MPDCCH tobe monitored in step (RA-4).

(RA-3) The UE Transmits Msg3 to the BS as Indicated by Msg2.

The UE transmits an (N)PUSCH in Msg3 as indicated by the UL grantacquired in step (RA-2) (e.g., see step S15 of FIG. 1 or step S1910 ofFIG. 11). The UE may include its ID (e.g., an SAE temporary mobilesubscriber identity (S-TMSI)) in Msg3, for contention resolution in step(RA-4).

(RA-4) The BS Detects Msg3 and Transmits Msg4 to the UE in Response toMsg3.

The UE attempts to detect Msg4 in response to Msg3 transmitted in step(RA-3) (e.g., see step S16 of FIG. 1 or step S1912 of FIG. 11). As instep (RA-2), the UE attempts to first detect an (N)PDCCH or an MPDCCH.An RNTI used for scrambling the (N)PDCCH or the MPDCCH may be atemporary cell RNTI (TC-RNTI) received in the RAR in step (RA-2). Thedetected (N)PDCCH or MPDCCH may include a UL grant indicating Msg3retransmission or may be a DL grant that schedules an (N)PDSCH includinga response to Msg3. That is, upon detection of the UL grant, the UE mayperform step (RA-3) again as indicated by the UL grant, and upondetection of the DL grant, the UE may detect the (N)PDSCH as indicatedby the DL grant and thus check the response to Msg3.

F.1 Measurement Report During Random Access Procedure

The UE may report information regarding DQI to the BS in step (RA-1) orstep (RA-3) in the random access procedure, and differently depending onthe reporting step. That is, the UE may transmit (or report) Msg1 (apreamble) and/or Msg3 including the information regarding DQI to the BS.

First, in the case of DQI reporting in step (RA-1), different Msg1resources (time and/or frequency and/or preamble) available to the UEmay be configured according to DQI in step (RA-0). That is, theresources of Msg1 transmitted by the UE may first be selected accordingto the CE level, and then resources of a level corresponding to the DQIamong one or more levels subdivided according to DQIs from thecorresponding resources may be configured. In other words, the resourcesof Msg1 transmitted by the UE may be configured in 2 steps (according toa CE level in the first step and then according to DQI in the secondstep). The DQI included in Msg1 represents high or low relative to aspecific value among various DQI levels proposed below, and an offsetlevel of the DQI based on the corresponding value may be transmitted tothe BS in Msg3 or in other resources at another time.

This is because the CE level selected by the UE is set only based on anRSRP, the CE level may represent only information about a signalstrength. For example, it may occur that despite a high signal strength,a signal/channel quality may be low due to interference between adjacentcells and a high spatial correlation between multiple antennas of theBS. This means that even when the CE level is low (the RSRP isrelatively high), the UE may have poor (N)PDCCH/MPDCCH or (N)PDSCHreception performance in step (RA-2) or step (RA-4). That is, since thereception performance of the UE is more closely related to thesignal/channel quality than the signal strength, the resources of Msg1may further be classified according to a DL channel within the same CElevel, for the purpose of notifying the signal/channel quality to the BSin advance. The BS may efficiently perform DL scheduling by acquiringthe channel quality information from the detected resources of Msg1.

In another method, the UE may provide DQI in step (RA-3) so that the BSmay use the DQI for DL scheduling in step (RA-4). Other methods may beconsidered according to the type of a random access procedure.

The methods will be described below in greater detail.

F.1.1 Measurement Report During Contention-Based Random Access (CBRA)Procedure

As described above, the UE may report DQI in step (RA-3), and the DQImay be related to the reception performance of the (N)PDCCH/MPDCCHand/or the reception performance of the (N)PDSCH in step (RA-4).

That is, the reported DQI may include the following information. Thefollowing information is only classified for the convenience ofdescription, and the DQI may include all or part of the followinginformation.

(1) Reference Signal Received Quality (RSRQ)

An RSRQ is a value representing the channel quality of an actual DL RS,as a reference metric that may be directly or indirectly used for DLscheduling of a BS. Unlike a general CQI, an RSRQ does not require aconfiguration such as a specific reference MCS, PMI, or RI. Therefore,the RSRQ may be obtained with lower complexity than CQI estimation, andafter receiving the DQI, the BS does not request a constraint related toa transmission mode (TM) to be used for DL scheduling to the UE. TheRSRQ may be used as a more suitable DQI, particularly in a situation inwhich the reference MCS and PMI are not configured in the random accessprocedure.

A. RSRQ value of (NB-IoT) carrier or narrowband (NB) in which Msg2 hasbeen received.

A one-level difference between reported logical values may be a valueobtained by dividing an RSRQ range unequally.

i. Average RSRQ of hopped frequency, when Msg2 hops in frequency (e.g.NB).

ii. Or an RSRQ value measured in specific frequency resources (center 6RBs carrying a PSS/SSS, a frequency resource with the lowest/highest ofthe indexes of frequency hopping resources, or a value indicated in step(RA-0)).

The frequency resources may also be applied when the DQI includes not anRSRQ bus information about the reception performance of a specificchannel (e.g., the (N)PDCCH/MPDCCH or the (N)PDSCH) (e.g., a conditionfor satisfying a specific block error rate (BLER), such as a repetitionnumber or an aggregation level (AL)).

iii. Or information about a frequency resource with the highest RSRQ orthe RSRQ of each frequency resource

iv. Or the RSRQ of frequency resources to be used for (N)PDCCH/MPDCCHmonitoring in step (RA-4)

v. Or the RSRQ of frequency resources to be used for (N)PDSCH receptionin step (RA-4)

vi. Or the RSRQ of a frequency resource overlapped between frequencyresources used for (N)PDCCH/MPDCCH monitoring and frequency resourcesused for Msg2 reception in step (RA-4)

vii. Or the RSRQ of a frequency resource overlapped between frequencyresources used for (N)PDSCH reception in step (RA-4) and frequencyresources used for Msg2 reception

viii. The RSRQ of each frequency resource (e.g., NB) is derived from anRSRP and a received signal strength indicator (RSSI). The RSSI may bethe average of the RSSIs of specific frequency resources or acquiredfrequency resources, and the RSRP may be the RSRP of each frequencyresource. On the contrary, on the assumption that RSSI informationincluding noise and interference may be different for each frequencyresource, the RSSI may be the RSSI of each frequency resource.

(2) Information about (N)PDCCH, MPDCCH, or (N)PDSCH Reception in Msg2

A. The repetition number R and/or AL of the (N)PDCCH/MPDCCH or the(N)PDSCH when the (N)PDCCH/MPDCCH or the (N)PDSCH has been successfullyreceived.

A maximum repetition number Rmax of the (N)PDCCH/MPDCCH or the (N)PDSCHis obtained in step (RA-0), and the UE may successfully detect the(N)PDCCH/MPDCCH or the (N)PDSCH with a repetition number R less than themaximum repetition number Rmax. Therefore, the repetition number R maybe used to represent the DQI of the UE. When aggregation is applied (tothe (N)PDCCH/MPDCCH), information about an AL at which the(N)PDCCH/MPDCCH has been successfully received and detected may also beused. According to the number of bits used for a quality report (e.g.,the repetition number R and/or the AL) in Msg3, a reporting range and/orthe representation unit of the reported repetition number R and/or ALmay be configured differently.

i. The lower bound of the representation range may be set to a specificvalue X, not 1. This is because a value lower than X means that thechannel quality is already sufficiently good, and thus more detailedinformation may not be required. In other words, when the actual R valueis less than X, a logical value mapped to the lower bound (or a minimumvalue except for a value reserved to maintain backward compatibilitywith the legacy system) may be reported.

ii. The upper bound of the representation range may be limited to aR (anactual repetition number that the BS has used for the (N)PDCCH/MPDCCH or(N)PDSCH transmission, which may be less than or equal to Rmax andindicated by DCI). Alternatively, the upper bound of the representationrange may be limited to Rmax or a value that is K times (e.g., twice)larger than Rmax. The reason for allowing a value greater than Rmax isthat a repetition number available for scheduling of the (N)PDCCH/MPDCCHor (N)PDSCH in Msg4 (e.g., the maximum repetition number Rmax) may bedifferent from a repetition number for Msg2.

iii. Representation units may not be uniformly set within the allowedrepresentation range. That is, the unit/interval of R and/or an ALrepresented by one unit in a low range of reported logical values may bedifferent from the unit/interval of R and/or an AL represented by oneunit in a high range of reported logical values. This is because aninaccurate value (quantization error) at a low R value and/or AL has nosignificant effect on scheduling in step RA-4, but a one-step differenceat a high R value and/or AL may lead to a very different repetitionnumber applied to actual DL scheduling in step (RA-4).

The above proposed DQI representation may be applied to and cover all ofthe cases proposed below in which an R value or an AL is included in theDQI. Further, when an R value or an AL is selectively included in theDQI, it is necessary to define a reference AL and a reference R value toobtain an R value and an AL, respectively. That is, there may be a needfor a reference AL that the UE may assume in deriving an R valuesatisfying a specific performance requirement for the (N)PDCCH/MPDCCH.Likewise, in the case of deriving an AL, a reference R value that may beassumed by the UE may be required. Each of the reference AL and R valuesmay be derived from the maximum repetition number Rmax of the Msg2MPDCCH, configured independently by the BS, or derived from the ALand/and R values actually applied to the Msg2 MPDCCH transmission. Forexample, the DQI may selectively include an AL. In a more specificexample, when the R value satisfies a specific performance requirement,the DQI may include the AL together with the R value. In anotherexample, when R is a value (e.g., 1) that satisfies a specificperformance requirement, the DQI information includes the R valuewithout the AL, and the reference AL (e.g., 24) may be assumed as theAL. In this example, when the repetition number R of the (N)PDCCH/MPDCCHor (N)PDSCH at the time of successful reception of the (N)PDCCH/MPDCCHor (N)PDSCH satisfies a specific performance requirement (e.g., 1), thereference AL may be derived from R (e.g., 1).

The DQI is reported as the repetition number R and/or AL of the(N)PDCCH/MPDCCH or (N)PDSCH which the UE has successfully received inMsg2, because the value of R is too small to calculate a CQI on theassumption of an RSRQ and a channel in a specific format (e.g.,(N)PDCCH, MPDCCH, or PDSCH), and thus an RS should be received for anadditional time to measure an RSRQ or a CQI. That is, when the UE hassucceeded in receiving and detecting Msg2 in time resources less than aspecific value (configured by the BS or defined in the standard),reporting indirectly to the BS that the DL channel quality issufficiently good rather than measuring an RSRQ or a CQI may beprofitable in terms of power saving. To this end, the BS may reservespecific DQI value(s) to be received for such a report. That is, whenthe R value and/or the AL is sufficiently small, the UE may selectivelyreport an R value and/or an AL from among the reserved states. When thereserved states are not defined separately, a specific DQI value (avalue indicating a good channel quality) may be reported.

(3) Information about Reception Performance of (N)PDCCH/MPDCCH in Msg4

A. The UE may acquire frequency resources (e.g., an (NB-IoT) carrier orNB) available or likely to be used in step (RA-0) and/or step (RA-4).After all, since the first step in which the DQI transmitted in Msg3 maybe used is to schedule the (N)PDCCH/MPDCCH for step (RA-4), the DQI ofthe frequency resources that may be used in step (RA-4) may bepreferably reported. However, accurate information about frequencyresources to be used for MPDCCH monitoring in step (RA-4) may beindicated by the RAR of the Msg2 PDSCH in a system such as MTC, theremaining time until the Msg3 transmission after acquisition of theaccurate information may not be sufficient for calculating the DQI ofthe frequency resources. Therefore, the following methods may beconsidered.

i. The DQI of each frequency resource likely to be used in step (RA-4)may be calculated based on the information acquired in step (RA-0), andonly DQI corresponding to the information acquired from the RAR (e.g., afrequency resource to be monitored in step (RA-4)) may be reported.

ii. If frequency hopping is applied, frequency resources that have beenused for hopping before a time X from the Msg3 transmission may beexcluded from DQI measurement and reporting. Alternatively, when X isless than a specific value, DQI reporting may be skipped, or the maximumof reportable DQI values may be limited to a specific value according toX.

iii. Msg2 includes the (N)PDCCH/MPDCCH and the (N)PDSCH. DQI referenceresources used for DQI measurement may be limited to the(N)PDCCH/MPDCCH, and further to resources within a time Y at the startof the (N)PDCCH/MPDCCH transmission (or at the start of a configuredMsg2 monitoring period). This may be done to lower the processing powerof the UE as much as possible. Alternatively, if the processing power ofthe UE is sufficient, even though the UE has succeeded in detecting the(N)PDCCH/MPDCCH before Rmax, the UE may be configured to additionallyreceive a longer period/more resources (less than Rmax) and measure DQI.Further, a time/frequency in which the (N)PDSCH is received may also beincluded in the DQI reference resources (a hypothetical resource thatmay be used for DQI measurement or transmission of a channel related tothe DQI). Particularly in a situation where although the Msg2(N)PDCCH/MPDCCH frequency resources are not fully included in the Msg4(N)PDCCH/MPDCCH frequency resources, the (N)PDSCH frequency resourcesmay be partially included in the Msg4 (N)PDCCH/MPDCCH resources, theneed for the DQI reference resource extension (to include even the(N)PDSCH resources) may be pressing.

B. As in the above proposal, channel quality information measured inmultiple frequency resources may be reported in the following methods.

i. The channel quality information may all be reported on a frequencyresource basis.

ii. Alternatively, the average or representative value of the measuredvalues of the respective frequency resources may be reported as thechannel quality information. (An RSSI may be an average value, whereasan RSRP may be measured independently on an NB basis. When an RSRQ orreception performance-related information is reported, noise informationmay be calculated based on the average value, and quality informationmay be calculated based on the value measured on an NB basis.)

iii. Or DQI differences (e.g., expressed as delta values or offsets fromthe average or representative value) together with the average orrepresentative value of the measured values of the respective frequencyresources may be reported for the remaining or all frequency resources.

iv. Or DQI difference of a specific frequency resource (e.g., expressedas a delta value or offset from the average or representative value)among DQI reference resources, together with the average orrepresentative value of the measured values of the respective frequencyresources may be reported for the remaining or all frequency resources.

v. Or only DQI corresponding to the information acquired from the RAR(frequency resources to be monitored in step (RA-4) or a specificfrequency resource indicated for reporting by the standard or systeminformation (e.g., an anchor carrier, center 6 RBs carrying a PSS/SSS,frequency resources used for Msg2, or a frequency resource closest tothe frequency resources used for Msg2 among frequency resources to beused for Msg4) may be reported.

vi. Or the average value of the measured values of the respectivefrequency resources may be reported.

vii. Or among the measured values of the respective frequency resources,the channel qualities and indexes of the best N frequency resources maybe reported (N may be configured by system information or indicated byMsg2).

viii. Or among the measured values of the respective frequencyresources, the channel qualities and indexes of the poorest N frequencyresources may be reported (N may be configured by system information orindicated by Msg2).

C. Based on the information acquired before step (RA-3) process, thefollowing may be performed.

i. The channel quality information measured as in the above proposal mayinclude a (UE-preferred) minimum R value and/or a minimum AL from whicha BLER of Z % (e.g., 1%) may be expected with respect to a specificreference DCI format (e.g., the DCI format of the (N)PDCCH/MPDCCCHexpected in Msg4) and/or port information about an RS (e.g., DMRS)and/or a resource allocation type (e.g., distributed or localized)and/or an (N)CCE/ECCE index. For the reference DCI format, assumption ofa specific DMRS port may be allowed.

ii. When the (UE-preferred) R value of the Msg4 (N)PDCCH/MPDCCH in step(RA-4) is reported, R may be represented as information about a ratio toRmax to be used in step (RA-4), which has been obtained before step(RA-3). That is, in regards to the logical value range of reported DQI,an actual R value may be interpreted differently according to Rmax to beused in step (RA-4), which has been obtained in step (RA-3). In theabove proposal, the units of the logical values may not be uniformlydistributed in an actual representation range of R.

Similarly to the description in (2), when a repetition number R or an ALis selectively included in DQI, it is necessary to define a reference ALand a reference R value in obtaining the R value and the AL,respectively. That is, a reference AL value that may be assumed by theUE may be required in deriving an R value that satisfies a specificperformance requirement for the (N)PDCCH/MPDCCH. Likewise, a reference Rvalue that may be assumed by the UE may be required in deriving an AL.Each of the reference AL and R values may be derived from Rmax of theMsg2 MPDCCH, configured independently by the BS, or derived from an ALand/or an R value actually applied to the Msg2 MPDCCH transmission. Forexample, the DQI may selectively include an AL. In a more specificexample, when R is a value (e.g., 1) that satisfies a specificperformance requirement, the DQI may include an AL together with an Rvalue. In another example, when R is a value (e.g., 1) that satisfies aspecific performance requirement, the DQI may include an R value withoutan AL, and the reference AL (e.g., 24) may be assumed as the AL. In thisexample, if R of the (N)PDCCH/MPDCCH or the (N)PDSCH at the time ofsuccessfully receiving the (N)PDCCH/MPDCCH or the (N)PDSCH at the UE isa value (e.g., 1) satisfying a specific performance requirement, thereference AL may be derived from the R value (e.g., 1).

(4) Information about Reception Performance of N(PDSCH) in Msg4

A. In step (RA-0), the UE may acquire frequency resources (e.g., an(NB-IoT) carrier or NB) available or likely to be used in step (RA-4).In MTC, a frequency resource, NB in which the Msg4 PDSCH may bescheduled within the LTE system bandwidth is indicated by the Msg4MPDCCH. In both NB-IoT and MTC, because (N)PDSCH scheduling information(e.g., an MCS, a TBS, resource allocation, and a repetition number) isindicated by a DL grant, the DQI transmitted in Msg3 may also be used inthe Msg4 (N)PDSCH scheduling. Accordingly, the DQI transmitted in Msg3may include the following information.

i. The DQI of each frequency resource likely to be used in step (RA-4)may be calculated based on the information acquired in step (RA-0), andwhen additional information (e.g., a frequency resource to be monitoredin step (RA-4)) is acquired from the RAR, only the DQI of the frequencyresource may be reported.

ii. If frequency hopping is applied, frequency resources that have beenused for hopping before a time X from the Msg3 transmission may beexcluded from DQI measurement and reporting. Alternatively, when X isless than a specific value, DQI reporting may be skipped, or the maximumof reportable DQI values may be limited to a specific value according toX.

iii. Msg2 includes the (N)PDCCH/MPDCCH and the (N)PDSCH. DQI referenceresources used for DQI measurement may be limited to the(N)PDCCH/MPDCCH, and further to resources within a time Y at the startof the (N)PDCCH/MPDCCH transmission (or at the start of a configuredMsg2 monitoring period). This may be done to lower the processing powerof the UE as much as possible. Alternatively, if the processing power ofthe UE is sufficient, even though the UE has succeeded in detecting the(N)PDCCH/MPDCCH before Rmax, the UE may be configured to additionallyreceive a longer period/more resources (less than Rmax) and measure DQI.Further, a time/frequency in which the (N)PDSCH is received may also beincluded in the DQI reference resources. Particularly when the Msg2(N)PDCCH/MPDCCH frequency resources do not hop or only frequencyresources less than a specific ratio to the LTE system bandwidth areused, the need for the DQI reference resource extension (to include eventhe (N)PDSCH resources) may be pressing.

B. As in the above proposal, channel quality information measured inmultiple frequency resources may be reported in the following methods.

i. The channel quality information may all be reported on a frequencyresource basis.

ii. Alternatively, the average or representative value of the measuredvalues of the respective frequency resources may be reported as thechannel quality information. (An RSSI may be an average value, whereasan RSRP may be measured independently on an NB basis. When an RSRQ orreception performance-related information is reported, noise informationmay be calculated based on the average value, and quality informationmay be calculated based on the value measured on an NB basis.)

iii. Or DQI differences (e.g., expressed as delta values or offsets fromthe average or representative value) together with the average orrepresentative value of the measured values of the respective frequencyresources may be reported for the remaining or all frequency resources.

iv. Or only DQI corresponding to the information acquired from the RAR(frequency resources to be monitored in step (RA-4) or a specificfrequency resource indicated for reporting by the standard or systeminformation (e.g., an anchor carrier, center 6 RBs carrying a PSS/SSS,frequency resources used for Msg2, or a frequency resource closest tothe frequency resources used for Msg2 among frequency resources to beused for Msg4) may be reported.

v. Or the average value of the measured values of the respectivefrequency resources may be reported.

vi. Or among the measured values of the respective frequency resources,the channel qualities and indexes of the best N frequency resources maybe reported (N may be configured by system information or indicated byMsg2).

vii. Or among the measured values of the respective frequency resources,the channel qualities and indexes of the poorest N frequency resourcesmay be reported (N may be configured by system information or indicatedby Msg2).

C. Based on the information acquired before step (RA-3), the followingmay be performed.

i. The channel quality information measured as in the above proposal mayinclude a minimum repetition number R (UE-preferred) and/or a minimum ALand/or RS (e.g., CRS or DMRS) port information and/or a resourceallocation type (e.g., distributed or localized) and/or a PMI and/orfrequency resource information (e.g., an NB or RB index requiring thesmallest amount of resources (i.e., a small repetition number R and/or alow AL), from which a BLER of Z % (e.g., 1%) may be expected withrespect to a specific reference format (e.g., a TBS and/or an MSC and/ora repetition number and/or a DMRS port of the (N)PDCCH/MPDCCCH expectedin Msg4, which may be predefined in the standard or configured by systeminformation or Msg2). When the specific reference format is notdesignated or information corresponding to a CQI, such as an MCS is notspecified for the reference format, a CQI and/or an RI may be includedin the DQI.

1. When a CQI is estimated based on channel information estimated fromthe CRS, precoding information (e.g., the correlation between the CRSand the DMRS, such as DMRS port information or a PMI) that the UE willassume may be given in advance.

ii. When the (UE-preferred) R value of the Msg4 (N)PDCCH/MPDCCH of step(RA-4) is reported, R may be represented as information about a ratio tothe maximum repetition number Rmax to be used in step (RA-4), which hasbeen obtained before step (RA-3). That is, in regards to the logicalvalue range of reported DQI, an actual R value may be interpreteddifferently according to Rmax to be used in step (RA-4), which has beenobtained in step (RA-3). In the above proposal, the units of the logicalvalues may not be uniformly distributed in an actual representationrange of R.

D. In the above proposal, when the DQI includes information related to(N)PDSCH reception performance, the UE may estimate the DQI, assuming aspecific TM. For example, the UE may always assume a fallback TM (e.g.,TM1 or TM2) as the TM used in the random access procedure or may derivea fallback TM or a reference TM according to the number of transmission(Tx) antennas (e.g., the number of CRS antenna ports) of the BS. Then,the UE may measure the DQI based on the TM. Further, the BS may directlyindicate a reference TM available for DQI measurement.

In the above proposal, when the UE fails in receiving the response(Msg4) to Msg3 or retransmits Msg3, the DQI may be treated as follows.

(1) When Msg3 is retransmitted, the following operations may beperformed.

A. When the DQI is channel-encoded together with data of Msg3 in thephysical layer, the DQI used in the previous transmission iscontinuously transmitted.

B. When the DQI is channel-encoded (e.g., in the form of UCI)independently of the data of Msg3 in the physical layer, the DQI used inthe previous transmission may be maintained or updated. When the DQI isupdated, reporting of a value equal to or less than the previousreported DQI may not be allowed (e.g., when a DL channel state is betterwith a lower DQI).

(2) When retransmission starts from Msg1, the following operations maybe performed

A. When the time resources (the maximum repetition number Rmax for Msg2or Msg4) and/or frequency resources (e.g., (NB-IoT) carrier or NB) ofMsg2 and/or Msg4 associated with Msg1 used in the retransmission arechanged, DQI may be newly measured.

B. Otherwise, reporting of a value equal to or less than the previousreported DQI may not be allowed. Further, reporting of a value equal toor larger than the previous reported DQI without DQI re-measurement maybe allowed (e.g., when a DL channel state is poorer with a higher DQI).

In all of the above proposals, when a repetition number R and an AL areused as values representing DQI, the DQI may include the repetitionnumber R and the AL, separately, in combination, or as modified in asimilar concept of a code rate.

In the proposals, the MPDCCHs transmitted in Msg2 and Msg4 aretransmitted through DMRS ports, not CRS ports in MTC. In this case, theUE has difficulty in predicting MPDCCH performance using the CRS. Thatis, it may be difficult to derive, from the CRS, a specific conditionthat an MPDCCH decoding failure probability is equal to or less than aspecific value. Then, a reference channel from which performance isderived may be defined as a channel other than the MPDCCH, while DQImeasurement based on the CRS is allowed. For example, a referencechannel used for RLM (e.g., a PDCCH format based on which out-of-sync ischecked or a PDCCH format based on which in-sync is checked), a thirdPDCCH format, or a PDSCH format based on the assumption of a specific TMmay be defined, and information based on the CRS, from which receptionperformance may be predicted based on the above-enumerated channel maybe defined as DQI. The TM may be given as TM1 or TM2 according to thenumber of CRS ports.

F.1.2 Measurement Report During Contention-Free Random Access (CFRA)Procedure

To report DQI in a CFRA procedure, all of the methods proposed insection G.1.1 (Measurement Report During Contention-Based Random Access(CBRA) Procedure') may be applied. CFRA is for a case in which a BS hasallocated resources of Msg1 (e.g., time and/or frequency and/or preambleresources for Msg1) UE-specifically to a UE. For example, CFRA takesplace mainly for updating TA information about a UE in the RRC_CONNECTEDstate. That is, when DL scheduling is required for the UE in a situationthe BS has not received a UL transmission from the UE for a specifictime or longer or has not performed UL scheduling, CFRA may be used toupdate a UL TA and thus reduce performance degradation caused by timingmisalignment in reception of a feedback (e.g., ACK/NACK) and/or CSI fora later-scheduled DL transmission on a PUCCH and/or an (N)PUSCH. Thismeans that the BS plans to perform DL scheduling for the UE after theCFRA procedure, and reception of DQI in Msg3 even in the CFRA procedureat the BS may help to minimize the performance degradation of later DLscheduling.

However, the CFRA procedure may be different from the CBRA procedure inthat DQI reference resources may be added or redefined because the UEhas already registered to the cell and acquired UE-dedicated informationadditionally by an RRC message. For example, the BS may additionallyconfigure reference resources (e.g., different from DQI referenceresources used in CBRA) in which the UE will measure DQI to be reported,for the UE in the random access procedure. The DQI reference resourcesmay be configured by RRC signaling or DCI triggering Msg1.Alternatively, specific resources of DQI reference resource setconfigured by RRC signaling may be indicated as the DQI referenceresources by DCI. In this case, the DQI may be reported in Msg3 (or thefirst (N)PUSCH transmitted after Msg2) in the form of UCI, not a MACmessage.

When the DQI includes information related to (N)PDSCH receptionperformance, the UE may estimate the DQI by assuming a specific TM. Forexample, the UE may always assume a fallback TM (e.g., TM1 or TM2) asthe TM for the random access procedure or derive a fallback TM or areference TM according to the number of Tx antennas (for example, thenumber of CRS antenna ports) of the BS, to measure the DQI based on theTM. Further, the BS may directly indicate a reference TM available forDQI measurement to the UE, or the UE may measure the DQI by assuming aTM used in the RRC_CONNECTED state.

The reference TM referred to in the process of deriving DQI in the CBRAand CFRA procedures may be specifically defined according to the numberof CRS ports of the BS as follows.

If the number of CRS ports is one, TM1 is assumed as the reference TM.

Otherwise, TM2 is assumed as the reference TM.

F.2 Measurement Report for UL Semi-Persistent Scheduling (SPS)

The BS may configure UL SPS to reduce resources required for ULscheduling of the UE. Because a UL grant for UL scheduling is nottransmitted each time, UL SPS may also be effective in reducing powerthat the UE uses for DL monitoring. UL SPS is a technique ofpreconfiguring multiple time-domain UL resources for a UE so that the UEmay transmit data in the UL SPS resources by its own decision withoutdynamic UL scheduling of a BS. UL SPS may be similar to SPS alreadydefined in the legacy LTE system or other systems, and independent ofthe RRC states. That is, in the present proposal, UL SPS refers to acommunication procedure and method in which a UE is allowed to perform aUL transmission without the need for UL scheduling of a BS each time.

However, when UL SPS activation/deactivation is supported by DCI or whenthere may be an HARQ feedback for UL SPS, the UE still needs to receivea DL signal or channel (e.g., (N)PDCCH, MPDCCH, (N)PDSCH, wake-up signal(WUS), or the like). As such, the BS may need to transmit a specificchannel to the UE even in the UL SPS situation. For link adaptation, allof the methods proposed in section F.1.1 (‘Measurement Report duringContention-Based Random Access (CBRA) Procedure’) and section F.1.2(‘Measurement Report during Contention-Free Random Access (CFRA)Procedure’) may be used.

However, because UL SPS time/frequency resources may be different fromtime/frequency resources to be used for Msg2 and/or Msg4 in the generalrandom access procedure (e.g., DL resources to be used for a DL feedbackfor a UL SPS reception at the BS (i.e., DL resources to be monitored bythe UE) may be independent of Msg2/Msg4 of the random access procedure),DQI reference resources for UL SPS may be configured independently. TheDQI reference resources for UL SPS may be directly defined in thestandard, configured by system information or an RRC message, directlyindicated by a channel (e.g., DCI) for activating/deactivating UL SPS,or a channel for HARQ feedback (e.g., (N)PDCCH or WIPDC CH).

Further, DQI reported in the UL SPS procedure may differ from DQIreported in the random access procedure, in terms of definition or arepresentation range. The DL channel (e.g., specific DCI) used for ULSPS activation/deactivation and/or HARQ feedback may be different from aDL channel (e.g., DCI with a type-2 common search space (CSS)) carryingMsg2 and/or Msg4 in the random access procedure. Herein, DQI may bemeasured with a DL channel defined for UL SPS as a reference (orreference channel), and then reported.

F.3 Measurement Report According to Receiver Type of UE

When the UE reports DQI during random access, a channel quality may bedifferently defined according to the receiver type of the UE. Thereceiver type of the UE may be one of receiver types defined to satisfya specific performance requirement in the standard. In LTE, for example,the receiver types may include maximal ratio combining (MRC), minimummean square error-interference rejection and combining (MMSE-IRC),enhanced MMSE-IRC (eMMSE-IRC), maximum likelihood (ML), and successiveinterference cancellation (SIC). The BS needs to know these receivertypes to avoid unnecessary resource waste by predicting the receptionperformance of the UE in advance during DL scheduling of the BS.Further, the BS needs to know these receiver types because it needs toprovide additional information to the UE according to the receiver typeof the UE in some cases.

(1) When the UE uses multiple Rx antennas, the UE may report DQI inconsideration of the multiple Rx antennas. Information about themultiple Rx antennas of the UE (e.g., information indicating whether anactual number of Rx antennas is indicated or a single reception antennais assumed) together with the DQI may be included in a measurementreport.

(2) The DQI reported by the UE may be derived based on the assumption ofa single Rx antenna. When an additional Rx antenna is available for theUE (i.e., multiple Rx antennas), it may be additionally reported. Forexample, the Rx antenna information may be a representation of anadditional gain (e.g., an RSRQ gain, an SNR gain, or reduction of arepetition number expected to receive Msg2 and Msg4 under a specificdetection performance requirement (e.g., BLER)) which may be obtainedwhen the multiple Rx antennas are used, or an indication simplyindicating that the multiple Rx antennas may be used in Msg2 and/orMsg4.

F.4 Conditions For Not Expecting DL Channel Quality Measurement

The proposed DQI measurement information may be used for DL schedulingand resource allocation (a code rate, a repetition number, and so on) ofthe BS. Although an additional operation is required for DQI measurementof a low-cost UE, the DQI measurement information may advantageouslyprevent the loss of power saving, caused by wrong link adaptation of theBS and hence DL reception signal detection failure (e.g., due to toosmall a repetition number) of the UE. However, when the maximumrepetition number of Msg4 is initially smaller than a specific value,link adaptation may not be important, and thus DQI measurement may beskipped to save power of the UE. On the contrary, when the maximumrepetition number of Msg4 is set to be larger than the specific value orthe RSRP or SNR of the UE is very low (e.g., when the UE has a high CElevel or the highest of CE levels configured in the cell), the accuracyof the DQI measurement information of the UE may be very low.Accordingly, there may be a certain condition for not measuring orreporting DQI to prevent unnecessary or meaningless power consumption ofthe UE, as follows.

(1) The maximum repetition number of the (N)PDCCH/MPDCCH or (N)PDSCH ofMsg4 is less than a specific value.

(2) The maximum repetition number of the (N)PDCCH/MPDCCH or (N)PDSCH ofMsg4 is larger than a specific value.

(3) The UE successfully receives Msg2 ((N)PDCCH/MPDCCH or (N)PDSCH) witha specific number of or fewer repetitions.

In the above conditions, each specific value may be defined in thestandard or may be information broadcast by the BS.

Alternatively, when an Msg3 transmission time indicated by Msg2 is notsufficient for DQI measurement, the UE may be allowed to skip DQImeasurement and reporting or to report a specific value (e.g., a valueindicating a poorest DL channel quality) as DQI. Herein, the “time thatis not sufficient for DQI measurement” may be a relative time intervalbetween Msg2 and Msg3, and may be defined as a UE capability.

F.5 DL Channel Quality and Method of Reporting the DL Channel Quality,When Random Access is Used for Special Purpose

When the UE attempts the random access procedure for mobile orientedearly data transmission (MO-EDT) (for transmitting UL data during therandom access procedure), an information size required for DQI reportingmay not be considered in selecting a TBS for Msg3 transmission. When thesmallest of TBSs allowed for the UE to use for Msg3 (TBSs larger thanthe size of data/information that the UE wants to transmit in Msg3) islarge enough to cover a size required to report DQI, except for the sizeof the data/information that the UE actually wants to transmit in Msg3,the UE may additionally include and transmit the DQI in Msg3.

When the BS performs mobile terminated early data transmission (MT-EDTfor transmitting DL data during the random access procedure) after theUE starts the random access procedure, the UE may be requested to reportDQI on UL even after Msg3 and/or Msg4. This is because in the case ofEDT, the UE may complete data transmission/reception with the BS in theRRC_IDLE state without entering the RRC_CONNECTED state and thus may notacquire detailed information for DL measurement as freely as in theRRC_CONNECTED state. That is, the UE may measure and report only DQI ata level allowed for random access, from the viewpoint of DQImeasurement. However, it may be configured that DQI to be reported afterMsg4 is measured in resources different from DQI reference resourcesused for DQI reporting in Msg3 in the proposed general random accessprocedure.

F.6 Reference Resources for DL Channel Quality Information

FIG. 13 illustrates a time flow of transmissions and receptions ofchannels and signals until Msg4 reception at the UE in the random accessprocedure, and the resource relationship of the channels/signals will bedescribed in terms of frequency. FIG. 13 is based on eMTC, and maycorrespond to the example of FIG. 1 or FIG. 11. In FIG. 13, a UL grantthat the UE receives after Msg3 transmission is scheduling informationfor Msg3 retransmission, using the same format as the Msg3/4 MPDCCH. InNB-IoT, the NPSS/NSSS/NPBCH is transmitted on an anchor carrier, andSIBs may be transmitted on the anchor carrier in FDD and on an anchorcarrier or a non-anchor carrier according to NPBCH information in TDD(e.g., see “D. Narrowband Internet of Things (NB-IoT)”). The Msg2 NPDCCHand NPDSCH, the Msg3/4 NPDSCH, and the Msg4 NPDSCH are all transmittedon the same NB-IoT carrier, which may be an anchor carrier or anon-anchor carrier. In MTC, the DL resource relationship in thefrequency domain is more complex, and may be summarized as follows.

PSS/SSS/PBCH

Center 6 RBs of LTE system bandwidth

SIB1-BR

SIB1-BR is transmitted in RBs distributed across the LTE systembandwidth, and the position of a used NB/RB may be different dependingon the DL bandwidth and the cell ID.

Other SIBs

The position of an NB/RB is determined according to schedulinginformation for the SI of SIB1-BR.

MPDCCH of Msg2

It is determined according to information configured in an SIB and apreamble index used for Msg1 transmission, and frequency hopping may beapplied according to rar-HoppingConfig.

PDSCH of Msg2

It is indicated by the MPDCCH of Msg2, and frequency hopping may beapplied according to rar-HoppingConfig

MPDCCH of Msg3/4

It may be transmitted in an NB identical to the MPDCCH NB of Msg2 or anNB shifted from the MPDCCH NB of Msg2 by a specific offset value, andthe offset value may be indicated by the UL grant of the RAR.

PDSCH of Msg4

It is indicated by the MPDCCH of Msg4 and frequency hopping may beapplied according to rar-HoppingConfig.

As described above, the DL frequency resources used before Msg4reception are defined in a complex relationship in the MTC system. Insome cases, Msg4 DL frequency resources to which DQI may be appliedfirst may be resources that the UE does not need to receive (accordingto the legacy random access procedure). That is, it may be determinedwhether the corresponding information may be effectively used for Msg4scheduling according to how DQI reference resources are defined. Inconsideration of the above, this section proposes DQI-referenceresources (DQI-RS). The proposed method may all be applied unlesscontradicting with other proposals described in the present disclosure.

The DQI-RS needs to be selected from among resources which may representthe channel quality of resources scheduled for transmission of theMsg3/4 MPDCCH and/or (N)PDSCH and which the UE may receive beforetransmitting Msg3. When Msg3/4 MPDCCH resources are the same as Msg2reception resources, the DQI-RS may be defined as part or all of theMsg2 MPDCCH/NPDCCH resources. The following is a method of selecting aDQI-RS, when Msg2 MPDCCH/NPDCCH resources are expected to be differentfrom Msg3/4 MPDCCH/NPDCCH and/or (N)PDSCH resources.

MTC

The center 6 RBs and/or an NB carrying system information and/or an NBcarrying the Msg2 PDSCH may be additionally included in the DQI RS.

It may be determined whether an additional DQI RS is actually applied,according to whether frequency hopping is applied to the Msg2 MPDCCHand/or the Msg2 PDSCH.

According to the above method, the DQI RS is basically resources that anMTC UE may expect to receive before Msg3 transmission. When the DQI-RSis selected in this manner, the UE may not need to perform an additionalreception operation for DQI measurement.

NB-IoT

RRC_IDLE state

(1) The BS may configure N (NB-IoT) carrier sets for the UE. The UE mayrandomly select a carrier from among the N carrier sets, measure the CQIof the carrier, and report the CQI. Alternatively, the UE may report theaverage and/or worst and/or best DQI of the N carrier sets.

The CQI may include information about a preferred carrier and/orrepetition.

To avoid ambiguity about the CQI states of an existing early CQI report,the above method may be applied only to the DL CQI of a non-anchorcarrier.

When the worst DQI and/or the best DQI is included, information aboutthe carrier in which the DQI has been measured may be additionallyreported, and directly included in the DQI value.

(2) Method of randomly selecting DQI reference carrier

The DQI reference carrier may be select based on a UE ID, the earliestreceivable DQI-RS may be selected, or a carrier with a small/large Msg2NPDCCH maximum repetition number may be selected first.

For two or more DQI-RS within a specific time, a DQI-RS carrier isselected based on the UE ID.

(3) When the UE acquires DQI for two or more DQI-RS carriers, the DQI-RScarriers may be prioritized as follows, for DQI reporting.

The best DQI, the DQI of a carrier that has been measured for thelongest (i.e., a carrier expected to have the highest DQI measurementaccuracy), or the DQI of the most recently updated carrier.

(4) When a CQI is selectively measured in a DL carrier or a set of DLcarriers indicated by the BS, an NPRACH carrier is selected from amongUL carriers associated with the corresponding DL carrier, and Msg1 istransmitted on the NPRACH carrier.

In general, a UL carrier is first selected for Msg1 and then DQI ismeasured in a DL carrier corresponding to the UL carrier in the randomaccess procedure. In the above method, however, when it is determined toreport the DQI of a specific DL carrier (e.g., a DL carriercorresponding to the best DQI) among multiple DL carriers, a UL carrierrelated to the DL carrier is selected.

(5) The BS may differentiate the configuration of a DQI-RS carrier setfor each UL carrier for Msg1

RRC_CONNECTED state

(1) When the BS indicates NPDCCH order-based Msg1 transmission, the BSmay directly indicate a DQI-RS carrier, and the UE may derive DQI fromthe DQI-RS carrier.

(2) After Msg3 transmission, the BS may change the DL carrier of the UEto the corresponding carrier.

(3) In the RRC connected mode, the UE may receive an indicationindicating a DQI-RS carrier to be used for DQI measurement in theRRC_IDLE state from the BS.

F.7 Method of Indicating DL Quality Information Reporting

Considering a computation time for DQI estimation and a time taken forgenerating a signal/channel for reporting DQI in Msg3 at the UE, whenthe UE may obtain an indication of DQI reporting may be an importantfactor. Particularly when additional information is required for DQImeasurement, the UE needs to obtain the information as soon as possible.This section proposes a method of indicating DQI reporting. The proposedmethod may all be applied unless contradicting with other proposalsdescribed in the present disclosure.

Method of using a bit/state of a UL grant included in an RAR

When the index of an Msg3/4 MPDCCH NB is a specific value, this isindirectly recognized as a DQI reporting indication. Characteristically,when a specific number or more Msg3/4 MPDCCH NBs are included in RARmonitoring NBs or when the interval between an RAR monitoring NB and anMsg3/4 MPDCCH NB is less than or equal to a specific value, it isdetermined that DQI reporting is indicated.

Method of using a reserved bit (s) of an RAR

In the case where (N)PRACH resources are used to request an EDT, whenMsg2 indicates that the EDT request of the UE has been accepted by theBS, it is recognized as a DQI reporting indication.

Since the connected mode is generally not entered in EDT, an opportunityto receive DQI/CQI as soon as possible in this manner may be required.

If Msg2 is received for (N)PRACH resources which are not used for an EDTrequest, a specific reserved bit of the RAR may be interpreted asindicating DQI reporting.

Method of indicating the configuration of DQI to be reported by a UE

A CQI and a repetition number may be selectively indicated in DQI.

(1) In a specific CE mode, a CQI or a repetition number may be fixedlyindicated. In a specific example, only the CQI may be reported in a CEmode that supports a relatively small repetition range or no repetition,or only the repetition number may be reported in a CE mode that supportsa relatively large repetition range.

A DQI report mode may be indicated.

(1) DQI reporting may be indicated for a wideband and/or a preferred NBand/or an NB of a DQI RS closest to an Msg.3/4 MPDCCH NB and/or aspecific NB of the DQI RS and/or an NB used for SIB reception and/or thecenter 6 RBs.

When it is necessary to divide the method of indicating DQI measurementand reporting into a step of configuring a measurement and a step ofindicating reporting, this may be realized in the following manner.

A reserved bit of the RAR may be used to trigger DQI reporting, with thefollowing features.

Whether the BS may receive/support a DQI report or a relatedconfiguration may be signaled (semi-)statically by high-layer signaling(e.g., system information or an RRC message), and on/off of DQIreporting may be indicated dynamically by a CSI report field in the ULgrant of the RANR (in CE Mode A in eMTC) or the reserved bit of the RAR.

When the RAR is a response to an EDT request, a DQI report configurationindicated by high-layer signaling, not the reserved bit of the RAR maybe followed (i.e., when DQI measurement and/or reporting is configuredfor the UE by higher-layer signaling, a decision as to whether to reportDQI may not be based on an indication of a dynamic signal, which may beapplied when the RAR does not have a reserved bit or the UL grant of theRAR does not have the CSI report field, as in eMTC CE Mode B).

When the CSI report field of the UL grant in the RAR is used as triggerinformation for DQI reporting, the reserved bit of the RAR may be usedfor the purpose of providing additional information related to a DQIreport configuration (this is also similarly applicable to a reversecase in which usages of the CSI report field of the UL grant and thereserved bit of the RAR are switched).

This may be used to dynamically change a related configuration, whenthere are one or more DQI report configurations.

A DQI report configuration may include information indicating whether toreport DQI, a DQI value range, the number of DQI bits, CSI resources(e.g., an NB set, a reference TM, and an NB-IoT DL carrier set), and aDQI report mode (e.g., a wideband or subband/NB (selected or preferredby the BS or the UE)).

Although the DQI report configuration may be determined by the CSIreport field in the UL grant of the RAR and the reserved bit of the RAR,the DQI report configuration may be determined differently according tothe TBS and/or duplex mode of Msg3, indicated by the UL grant of theRAR.

When the TBS of Msg3 is equal to (or smaller than) a specific value, DQIreporting may be disabled.

According to the TBS of Msg3 and/or the contents (e.g., RRC Resume, RRCReconfiguration Request, or the like) of Msg3, a DQI report mode (e.g.,a wideband or subband/NB (selected or preferred by the BS or the UE)), aDQI value range, and the number of DQI bits may be different.

F.8 Interpretation of Msg3/4 MPDCCH NB, when DL Quality InformationReporting is Indicated

As described above, the DQI may be used directly for the Msg3/4 MPDCCH.If the DQI-RS is different from the Msg3/4 MPDCCH (frequency) resources,the Msg3/4 MPDCCH resources may be derived based on a reported DQI-RS tomore actively use the DQI. That is, when the BS has configured a set ofMsg3/4 MPDCCH resources by system information, it is not easy to changethe set of Msg3/4 MPDCCH resources. Therefore, when there is nomisunderstanding about a DQI-RS between the BS and the UE, the UE may beallowed to interpret the Msg3/4 MPDCCH and/or PDSCH (frequency)resources differently from a value obtained from the system informationaccording to the DQI-RS of the DQI reported by the UE. The proposedmethod may all be applied, unless contradicting with other proposalsdescribed in the present disclosure.

The Msg3/4 MPDCCH and/or PDSCH (frequency) resources may be interpretedas identical to or including some of Msg2 MPDCCH NBs (i.e., the Msg3/4MPDCCH NB index indicated by the UL grant in the RAR is interpreteddifferently).

When DQI has been reported, a frequency hopping field may be included inthe DCI of the Msg3/4 MPDCCH, or it may be allowed to use the frequencyhopping field even in the Msg3/4 reception step.

When information about a preferred NB is included in the DQI, the UE mayassume or receive an indication indicating that frequency hopping is offfor the Msg3/4 MPDCCH and/or the Msg4 PDSCH.

Characteristically in CE Mode B, a frequency hopping on/off field may beadded to the Msg4 DL grant or may be indirectly derived from acombination of other fields.

Characteristically in CE Mode B, the frequency hopping field in the Msg4DL grant may be used to interpret whether a PDSCH scheduled by the DCIhops in frequency.

F.9 Configuration of DL Quality Information

The MTC UE and the NB-IoT UE support various CE levels and CE modes. TheCE levels and CE modes reflect distances (i.e., SNRs) from the BS andmobility, and further, UE processing power. Accordingly, DQI which maybe measured or generated by the UE needs to be limited in considerationof such various types of information about the surroundings. Thissection proposes the configuration and range of information included inDQI. The proposed method may all be applied, unless contradicting withother proposals described in the present disclosure.

Configuration of DQI report information

The DQI report information may include only part of the following DQIconfiguration information and may be reported to the BS.

Information indicating whether the DQI has been configured based on aCQI or a repetition number may be included.

(1) A DQI table may be made to include CQIs and repetition numbers, anda CQI or a repetition number may be reported according to an indexselected in the DQI table by the UE. Characteristically, the lowest CQIin the DQI table may be configured to indicate a state similar to orbetter than a channel state indicated by the lowest repetition number inthe DQI table (e.g., in terms of BLER).

Reporting types may include (a) wideband CQI or repetition, (b) wideband(CQI or repetition) and UE-selected (or BS-selected) NB index and CQI orrepetition on the corresponding NB, (c) wideband (CQI or repetition)with PMI, and (d) wideband (CQI or repetition) without PMI.

The number of Rx antenna ports (characteristically, when the number ofRx antenna ports is larger than 1, the CQI (or repetition) is fixed tothe highest value (or lowest value)).

The DQI information configuration may be configured differentlydepending on a CE level and/or whether an Msg2 MPDCCH repetition (e.g.,an actual transmission number or a maximum repetition number) and Msg2MPDCCH hopping are performed and/or depending on the PRACH format andwhether PRACH repetition and PRACH hopping are performed.

When Msg1 has been transmitted in response to an EDT request or when therandom access procedure is in progress as a part of the EDT process, itmay be configured that a CQI is selected and reported.

Although the DQI UE may directly select a repetition number assumed forCQI measurement and indicate the repetition number together with a CQIin DQI to the BS, the repetition number may be configured directly bythe BS or derived by a specific parameter. That is, the repetitionnumber that the UE assumes for CQI measurement may be a specificpredetermined value, not a value that may be directly selected by theUE. The value may be broadcast directly from the BS or defined by arelationship determined according to a CE level and a parameter of achannel to be monitored or used as a reference for CQI calculation bythe UE.

DQI range

N sets of CQI (or repetition) value ranges are configured in an SIB, anda specific one of the N sets is indicated by the RAR.

(1) For each set, R_TM and/or R_DQI and/or R_CQI and/or R_Rep that theUE may assume in the DQI derivation process may be defined differently.

R_TM, R_DQI, R_CQI, and R_Rep represent a reference TM, a referenceDQI-RS, a reference CQI, and a reference repetition number,respectively. Only when the UE has part of the information, the UE mayestimate information suitable for DQI configuration information. Herein,a reference is a parameter that may be assumed to be used forhypothetical DL channel transmission in deriving the receptionperformance of a hypothetical DL channel that DQI is intended torepresent.

A different DQI set may be available according to the number of Rxantenna ports. In this case, the UE needs to additionally notify thenumber of Rx antenna ports or information about a used set.

The DQI range configuration and the number of sets may be differentdepending on a CE level and/or whether Msg2 MPDCCH repetition (e.g., anactual transmission number or a maximum repetition number) and Msg2MPDCCH hopping are performed and/or a PRACH format and whether PRACHrepetition and PRACH hopping are performed.

A corresponding specific value may be set as follows, when a differentspecific DQI reporting operation is performed according to whether thenumber of repetitions or subframes of an MPDCCH (or NPDCCH) and/or an(N)PDSCH received until the UE successfully demodulates/detects theMPDCCH (or NPDCCH) and/or (N)PDSCH of Msg2 is greater or less than aspecific value (e.g., when the UE reports the repetition number of ahypothetical MPDCCH (or NPDCCH) and/or (N)PDSCH or a value correspondingto subframes or repetitions or an AL received until the UE successfullydetects the MPDCCH (or NPDCCH) and/or (N)PDSCH).

The specific value may be set by the BS or predetermined to be aspecific ratio of the maximum repetition number of a channel (e.g.,MPDCCH (or NPDCCH) and/or (N)PDSCH) related to the RAR. (e.g., Thepredetermined value may be configurable by the BS or fixed in thestandard, and the range/value of the ratio may also be differentaccording to the maximum repetition number and/or frequency hopping ornon-frequency hopping of the channel related to the RAR (e.g., MPDCCH(or NPDCCH) and/or (N)PDSCH).)

When the UE reports the value corresponding to the subframes orrepetitions or AL received until successful MPDCCH (or NPDCCH) and/or(N) PDSCH detection as DQI, the corresponding value is specificallydetermined as follows.

When DQI is predefined/given as a plurality of repetition numbers, a DQIvalue is the smallest of values equal to or greater than an actualnumber of received subframes or repetitions among the predefined/givenvalues.

F.10 DL Quality Information Report Mode

In this section, various modes for reporting DQI are proposed. Asdescribed above, the MTC and NB-IoT systems support various CE levelsand CE modes, particularly, MTC has even the feature of frequencyhopping of DL NB resources and thus there is a need for supporting aproper DQI report mode for each configuration in consideration of itsfeatures. The proposed method may be applied to all the other proposals,unless contradicting with the other proposals described in the presentdisclosure.

In CE Mode A, CQI-based DQI is reported.

If frequency hopping is enabled (rar-HoppingConfig is set), thefollowing operations are performed.

(1) UE-selected subband feedback (aperiodic CSI report, Mode 2-0)

Legacy CSI reporting behavior

-   -   wideband CQI on all narrowband(s) in the CSI reference resource    -   preferred narrowband index within the set of narrowband(s) in        which MPDCCH is monitored    -   CQI value reflecting transmission only over the preferred        narrowband, CQI will be encoded differentially relative to        wideband CQI    -   here CSI reference resource is:        -   In the time domain and for a BL/CE UE, the CSI reference            resource is defined by a set of BL/CE downlink or special            subframes where the last subframe n-n_(CQI_ref),            -   where for periodic CSI reporting n_(CQI_ref) is ≥4:            -   where for aperiodic CSI reporting n_(CQI_ref) is ≥4:                -   where each subframe in the CSI reference resource is                    a valid downlink or valid special subframe:            -   where for wideband CSI reports:                -   The set of BL/CE downlink or special subframes is                    the set of the last ceil(R^(CSI)/N_(NB,hop)                    ^(ch,DL)) subframes before n-n_(CQI ref) used for                    MPDCCH monitoring by the BL/CE UE in each of the                    narrowbands where the BL/CE UE monitors MPDCCH.                    where N_(NB,hop) ^(ch,DL) is the number of                    narrowbands where the BL/CE UE monitors MPDCCH.            -   where for subband CSI reports:                -   The set of BL/CE downlink or special subframes is                    the set of the last R^(CSI) subframes used for                    MPDCCH monitoring by the BL/CE UE in the                    corresponding narrowband before n-n_(CQI_ref):            -   where R^(CSI) is given by the higher layer parameter                csi-NumRepetitionCE.        -   In the frequency domain, the CSI reference resource includes            all downlink physical resource blocks for any of the            narrowband to which the derived CQI value relates

Proposed Method

The UE follows a method similar to CSI report mode 2-0 for legacy BL/CEUEs, and the following modifications and additions are required.

R^(CSI): R^(CSI) lot may be defined cell-commonly, R^(CSI) may bedefined per each CE level, or Rest^(CSI) may be defined as a valuedependent on an RAR MPDCCH repetition number (an actual MPDCCHrepetition number or a maximum repetition numbermpdcch-NumRepetition-RA). This value may be signaled by RRC signalingsuch as an SIB or by Msg2.

Preferred NB: An NB may be selected from among CSI reference resourcesin the frequency domain, which is closest to an NB used to monitor theMsg3/4 MPDCCH derived from an Msg3/4 MPDSCH NB index in the informationreceived from the UL grant included in the RAR. The UE may calculate DQI(CSI) based on the CRS in only up to a specific step during MPDCCHmonitoring for Msg2 reception, and completely calculate wideband CSI andthe DQI (CQI) of the preferred NB after interpreting the RAR.

CSI reference resource: It may be replaced with the DQI-RS of thedisclosure.

(2) Wideband CQI without PMI (periodic CSI report, mode 1-0)

Legacy CSI reporting behavior

One wideband CQI conditioned on transmission rank 1

Proposed method

The UE follows a method similar to CSI report mode 1-0 for legacy BL/CEUEs, and the following modifications and additions are required.

R^(CSI): R_(CSI) may be defined cell-commonly, R^(CSI) may be definedper each CE level, or R^(CSI) may be defined as a value dependent on anRAR MPDCCH repetition number (an actual MPDCCH repetition number or amaximum repetition number mpdcch-NumRepetition-RA). This value may besignaled by RRC signaling such as an SIB or by Msg2.

(3) Wideband CQI with PMI (periodic CSI report, mode 1-1)

Legacy CSI reporting behavior

One wideband CQI and PMI within restricted subset of PMI if configured

Proposed method

The UE follows a method similar to CSI report mode 1-1 for legacy BL/CEUEs, and the following modifications and additions are required.

R^(CSI): It may be defined cell-commonly, on a CE level basis, or as avalue dependent on an RAR MPDCCH repetition number (an actual MPDCCHrepetition number or a maximum repetition numbermpdcch-NumRepetition-RA). This value may be signaled by RRC signalingsuch as an SIB or by Msg2.

R_TM: A reference TM may be defined. The reference TM may be signaled byRRC signaling such as an SIB or by Msg2 from the BS or determinedaccording to the number of CRS ports of the BS. Further, the BS mayindicate the reference TM to the UE in consideration of a PDSCH TM to beused after receiving Msg3.

PMI subset: It may be defined cell-commonly, on a CE level basis, oraccording to an RTM.

If frequency hopping is disabled, the following operations areperformed.

(1) UE-selected subband feedback (aperiodic CSI report, mode 2-0)

Legacy CSI reporting behavior

Wideband CQI on all narrowband(s) in the CSI reference resource

Preferred narrowband index

Differential CQI value=0

Proposed method

The UE follows a method similar to CSI report mode 2-0 for legacy BL/CEUEs, and the following modifications and additions are required.

R^(CSI): It may be defined cell-commonly, on a CE level basis, or as avalue dependent on an RAR MPDCCH repetition number (an actual MPDCCHrepetition number or a maximum repetition numbermpdcch-NumRepetition-RA). This value may be signaled by RRC signalingsuch as an SIB or by Msg2.

CSI reference resource: Since an Msg3/4 MPDCCH NB may have differentfrequency-domain resources from the Msg2 MPDCCH, the UE may beconfigured to additionally use a channel to which frequency hopping isapplied in the CSI reference resource. For example, there may be SIB1-BRand other SIBs.

Preferred NB: An NB may be selected from among CSI reference resourcesin the frequency domain, which is closest to an NB used to monitor theMsg3/4 MPDCCH derived from an Msg3/4 MPDSCH NB index in the informationreceived from the UL grant included in the RAR. The UE may calculate DQI(CSI) based on the CRS in only up to a specific step during MPDCCHmonitoring for Msg2 reception, and completely calculate wideband CSI andthe DQI (CQI) of the preferred NB after interpreting the RAR.

In CE Mode B, DQI based on a required repetition number is reported.

If frequency hopping is enabled (rar-HoppingConfig is set), thefollowing operations are performed.

(1) Operations in CE Mode B are the same as the aforementionedoperations in CE Mode A, but repetition (or a repetition number) insteadof a CQI is reported as DQI. In this case, DQI report may bemeasured/reported based on DQI instead of a CQI in the method describedin relation to CE Mode A. For example, the DQI report may include onlywideband DQI, or further include NB DQI measured in a preferred NB andinformation about the position of the preferred NB (e.g., preferred NBindex) as well as the wideband DQI. In addition, for example, thewideband DQI and/or the NB DQI may be measured according to the methoddescribed in section F.1, and may include the information (therepetition number R and/or the AL) described in section F.1. In a morespecific example, the wideband DQI and/or the NB DQI may include anRSRP/RSRQ value and/or reception information about the (N)PDCCH/MPDCCHor (N)PDSCH of Msg2 and/or information about the reception performanceof the (N)PDCCH/MPDCCH of Msg4 and/or information about the receptionperformance of the (N)PDSCH of Msg4.

(2) R^(CQI): A CQI value available as a reference needs to be defined.This value may be defined as a reference MCS used to report a repetitionnumber satisfying a specific target reception performance (e.g., BER) byan MCS (a code rate, the number of layers, and a modulation order). TheCQI value may be defined cell-commonly, on a CE level basis, or as avalue dependent on an RAR MPDCCH repetition number (e.g., an actualMPDCCH repetition number or a maximum repetition numbermpdcch-NumRepetition-RA). It may also be a value derived indirectly fromthe Msg2 MPDCCH. This CQI value may be signaled by RRC signaling such asan SIB or by Msg2. Alternatively, for example, the modulation order andTBS (or the number of bits derived from a corresponding fixed DCIformat) of the Msg2 MPDCCH may be used as parameters for the CQI value,and a reference AL may be independently given to the UE.

R_AL may be defined in all of the above methods.

R_AL refers to a reference AL for the MPDCCH. Information suitable forDQI configuration information may be estimated from R_AL. Herein,reference means a parameter that may be assumed for transmission of ahypothetical DL channel in deriving the reception performance of thehypothetical DL channel (e.g., MPDCCH) that DQI is intended torepresent.

When there are various DQI report modes (e.g., wideband orsubband/narrowband selected or preferred (by the BS or the UE)), a DCIreport mode may be determined as follows.

The DQI report mode may be determined by the NB (or NB-IoT carrier)relationship between Msg2 and Msg3/Msg4.

For example, when the NB (or NB-IoT carrier) of Msg2 and the NB (orNB-IoT carrier) of Msg3/Msg4 are different, wideband DQI may bereported. When the NB (or NB-IoT carriers) of Msg2 and the NB (or NB-IoTcarrier) of Msg3/Msg4 are the same, NB DQI may be reported.

Depending on whether the NBs (or NB-IoT carriers) of Msg2 and Msg3/Msg4are different, DQI may be selectively defined as a CQI or a repetitionnumber/AL, and a DQI value range may also be defined differently.

In the above description, a wideband may be based only on actual NBsused for Msg2 transmission by the BS. That is, even when the BS enablesfrequency hopping for a reference resource (e.g., a Type2 CSS) servingas a reference for DQI measurement, only some frequency resources (NB)may be used for the transmission. For example, when a repetition numberis small, the BS may not use all of NBs available for frequency hopping.

F.11 DL Quality Information Report for Non-BL UE

A non-BL UE operating in a CE mode may use two or more Rx antennas, andmeasure and report DQI based on the Rx antennas. The BS may not haveaccurate knowledge of the number of Rx antennas of the non-BL UE, and asuitable DQI value range may be different according to the number of Rxantennas used for DQI measurement. In this regard, DQI measurement andreporting of the non-BL UE may have the following features.

The BS may set the number of Rx antennas available for DQI measurementof the UE.

When the UE measures DQI, the UE may measure the DQI based on a singleantenna to reduce power consumption. However, if the DQI is a specificvalue or represents a worse quality, the UE may be forced or configuredto measure/report DQI using two or more Rx antennas.

F.12 Method Of Measuring and Reporting DL Quality Information in One orMore NB-IoT DL Carriers

The UE may be instructed to measure DQI in on one or more NB-IoT DLcarriers and report the DQI. Particularly, the network mayindicate/configure the DQI measurement and reporting to use the DQI asauxiliary information for DL carrier redirection.

The carrier set may be configured by higher-layer signaling (e.g.,system information or an RRC message) or carrier(s) to be measured andreported by the UE in the carrier set configured by the higher-layersignaling may be indicated by DCI (e.g., DCI triggering an (N)PDCCHorder-based (N)PRACH).

The carrier set (that the UE should measure) may include a combinationof an anchor carrier and one non-anchor carrier (an anchor carrier thatmay be expected to have been received by the UE in a CE level selectionprocess to reduce additional power consumption caused by measurement ofthe UE may be added to measurement carriers because the addition of theanchor carrier may not have a significant effect on the receptioncomplexity and power consumption of the UE.)

The measurement period of the anchor carrier may be limited to an(N)PRSRP period for CE level selection.

The measurement period of the non-anchor carrier may be limited to atime period after Msg2 reception.

An additional measurement gap or time may be given to perform the aboveadditional measurement.

If carrier(s) is given to an (N)PDCCH order-based (N)PRACH, anadditional time for the UE to transmit Msg3 after the DCI (e.g., theinterpretation of a scheduling delay may be extended or different) maybe set.

The UE may be allowed not to expect DL scheduling for a specific timebefore the random access procedure, which may be different according tothe position of an NB-IoT DL carrier to be additionally measured by theUE, an operation mode, and a carrier type (e.g., anchor carrier ornon-anchor carrier) (i.e., the UE may be allowed not to receive any orpart of a specific search space).

The UE may report the measurement result of carrier(s) other than acarrier on which Msg2 associated with Msg1 has been received.

The UE may be configured to select a preferred NB-IoT DL carrier basedon the measurement result and report only corresponding information(because there may be a limit on the configuration of a field formeasurement reporting).

When the DL channel quality of the carrier is to be reported togetherwith the above information, and when the specific interpretation of theDL channel quality information is changed according to the configurationof Msg2 (e.g., the maximum repetition number of the Msg2 NPDCCH), the DLchannel quality information may be determined/interpreted based on theMsg2 configuration of a DL carrier associated with the Msg1 transmissionor based on the Msg2 configuration of a DL carrier selected (orreported) based on a measurement.

If there is no Msg2 configuration for the selected carrier, the Msg2configuration of a DL carrier associated with the existing Msg1transmission may be followed, or an Msg2 configuration to be referred tomay be defined or given separately.

The UE may be allowed to select a preferred NB-IoT DL carrier based onthe measurement result and transmit Msg1 on a UL carrier correspondingto a DL carrier in which Msg2 may be expected.

When the preferred NB-IoT DL carrier has been reported, the UE may beconfigured to perform NPDCCH monitoring related to Msg2 and/or Msg3/4 onthe carrier.

The BS may present a reference value for selecting a preferred NB-IoT DLcarrier. For example, the BS may limit a repetition number estimated bythe UE (which the UE needs to decode a hypothetical NPDCCH in aType2-CSS with a BLER of 1% upon the NB-IoT DL carrier) not to exceed aspecific value.

If only a specific DL carrier is measured (other than an Msg2 carrierassociated with Msg1), the UE may measure/report the DQI of theindicated carrier.

If DQI is interpreted/determined based on an Msg2 configuration, Msg2configuration information may still be based on the carrier of Msg2associated with Msg1 or the Msg2 configuration of the indicated(measured) carrier.

The preferred carrier may be the most UE-preferred carrier or the leastUE-preferred carrier in terms of reception performance.

A preferred carrier is a carrier predicted to have the best DL receptionperformance, and a non-preferred carrier is a carrier predicted to havethe worst DL reception performance. When the least preferred carrierinformation is reported, the DQI may not include a repetition number ormay include a conservative value (e.g., the largest of the repetitionnumbers of carriers except for the least preferred carrier) out of DQI(repetition numbers) about other carriers. The reason for reportingnon-preferred carrier information is that when the BS redirects the DLcarrier of the UE, the non-preferred carrier information may be used asinformation indicating that the UE does not want the carrier to beconfigured as a DL carrier.

The DQI report may include DQI measured in two or more NB-IoT DLcarriers.

The DQI may be transmitted at the same time or may be transmitted at adifferent time or in different resources.

When the DQI is reported at the same time, the value range and/orrepresentation interval of the DQI may be smaller or narrower than theDQI of one NB-IoT DL carrier.

When there are multiple carriers on which reception of Msg2 may beexpected, corresponding to a carrier available for Msg1 transmission,the UE may select a DL carrier with the best DL channel quality (e.g.,satisfying a specific reception performance of a specific channel withthe smallest repetition number) among the multiple DL carriers and thenattempt to transmit Msg1 on a UL carrier corresponding to the selectedDL carrier.

The UE may then indicate that Msg1 is transmitted on the UL carrierbecause of the best DL channel quality of the DL channel correspondingto the UL carrier during the CQI transmission (e.g., in Msg3). Thisinformation may be reported together with the CQI required for theselected DL carrier (e.g., the smallest repetition number with whichreception of a specific channel may be expected, while satisfying aspecific reception performance).

This may be used as indirect information requesting the BS not toallocate the other DL carriers to the UE after the random accessprocedure.

F.13 Physical UL Channel for DL Quality Information Report

When a CQI is transmitted in Msg3, corresponding information may betransmitted on the (N)PUSCH largely by rate-matching or puncturing.Rate-matching is to allocate data to be transmitted in Msg3 to REsexcept for REs carrying the CQI in the (N)PUSCH. In this case, there isa need to avoid a mismatch in the number of REs to be used for datatransmission between the UE and the BS. For example, when there is amismatch in the number of REs, the BS may determine a wrong code rate tobe referred to for data decoding, thereby failing in the decoding.Puncturing is a scheme of performing data mapping without taking intoaccount the number and positions of REs required for CQI transmissionwhile determining the number of REs available for the data to betransmitted in Msg3. Puncturing is advantageous in that the BS does notdetermine a wrong code rate for data decoding of Msg3 in spite of noknowledge of whether the UE will transmit a CQI. The above-describedrate-matching and puncturing may be selectively applied depending onwhether the BS may be aware whether the UE transmits a CQI before the BSattempts to decode data. For example, when a CQI is transmitted in Msg3in the initial random access procedure, the CQI may be transmitted bypuncturing. When a CQI is transmitted in Msg3 in the RRC connected modeby a BS request, rate-matching may be used. Further, when the UEtransmits a CQI in BS-preconfigured UL resources (PUR) in the RRC idlemode, rate-matching may be applied. If the PUR is configured in the RRCidle mode, not in the RRC connected mode, the BS may not haveinformation about the UE capability of supporting CQI measurement andreporting. Therefore, puncturing may be applied.

F.14 CQI Reporting in RRC Connected Mode

The BS may redirect the NB-IoT UE to a non-anchor carrier in the randomaccess procedure. That is, a non-anchor carrier other than the DLcarrier on which the UE has received Msg2 and Msg4 (i.e., other than aDL carrier from which the CQI has been derived and reported in Msg3 bythe UE) may be allocated to the UE, and then the UE may be requested toperform a subsequent operation on the configured non-anchor carrier. Inthis case, since the BS has no knowledge of the CQI of the non-anchorcarrier of the UE, the BS may need to request the UE to measure a CQI inthe configured carrier and report the CQI, apart from the CQI reportedby the UE in the random access procedure. This may be performed based onthe procedure of reporting a CQI on an (N)PUSCH (hereinafter referred toas Msg3) indicated by Msg2 in an (N)PDCCH order-based random accessprocedure. In this case, whether to report a CQI in Msg3 may beindicated using a reserved bit (‘R’ bit) unused in the MAC RAR of Msg2.However, since there may not be enough time to measure the CQI aftersuccessful detection of Msg2, whether to report the CQI in Msg3 may beindicated by a specific state or bit that is not used or is always setto a specific value in DCI that triggers Msg1 transmission (e.g., DCIrequesting (N)PDCCH order-based Msg1 transmission).

The CQI measured by the UE may be defined differently from the CQIreported in the random access procedure. For example, since there is noinformation about a USS in the initial random access procedure, a CQImay be defined based on a parameter related to a resource configurationfor detecting Msg2 (e.g., a maximum repetition number for a type-2 CSS),whereas when CQI measurement and reporting are requested in the RRCconnected mode as described above, a CQI may be defined based on analready configured USS-related parameter (e.g., a maximum repetitionnumber). For example, the CQI may be defined as an actual repetitionnumber with which a PDCCH (e.g., MPDCCH or (N)PDCCH) related to Msg2 hasbeen successfully detected or a repetition number required to decode a(hypothetical) PDCCH (e.g., MPDCCH or (N)PDCCH). In this case, the CQImay be defined based on a maximum repetition number. In a more specificexample, the CQI may be defined as a ratio to the maximum repetitionnumber Rmax. When the actual repetition number with which the PDCCH(e.g., MPDCCH or (N)PDCCH) related to Msg2 has been successfullydetected or the repetition number required to decode the (hypothetical)PDCCH (e.g., MPDCCH or (N)PDCCH) is reported as one of {1, 2, 4, 8, . .. }, the CQI may be defined as one of {Rmax, Rmax/2, Rmax/4, Rmax/8, . .. }.

Further, the CQI may be defined based on a CSS or a USS which has alarger or smaller maximum repetition number, or one of the CSS and theUSS may be selected by specific signaling from the BS. Even when the CQIis defined based on the USS, an NRS received for CQI measurement by theUE may be included in CSS Type 2 because the NRS may always be expectedin a type 2 CSS on the non-anchor carrier. When the BS indicates anNPDCCH order-based NPDCCH transmission, the BS may configure the CElevel of Msg1 resources to be different from an actual CE level of theUE. However, the UE may derive a CQI based on its DL CE level, not theCE level related to Msg1, indicated by the BS.

F.15 Method of Reporting CQI in PUR in RRC Idle Mode

When the UE transmits an (N)PUSCH in a PUR configured by the BS in theRRC idle mode, and when the UE is to monitor a DL channel for such asreason as reception of feedback information for the PUR transmission,the BS may need a CQI from the UE. That is, the BS may use the DL CQI ofthe UE to configure a repetition number and/or an AL and/or a code rate(which may be determined by a resource size and an MCS), for an(N)PDCCH/MPDCCH and/or an (N)PDSCH. The BS needs the CQI for a similarreason to a reason for which the BS needs a CQI of the UE in the initialrandom access procedure. However, since a used UL channel structure isdifferent from that in the initial random access procedure in terms ofPUR transmission, the following features may be needed additionally.

1) CQI definition

A. Since the DL feedback channel structure may be different according toa PUR type, the CQI definition may be related to the PUR type.

{circle around (1)} There are a PUR type in which time/frequencyresources are UE-dedicated, a PUR type in which time/frequency resourcesare sharable among multiple UEs, with spatial and/or code resourcesconfigured in a UE-dedicated manner, (e.g., collision may occur but withno contention), and a PUR type in which all resources are sharable amongmultiple UEs (e.g., contention may occur).

{circle around (2)} Depending on a PUR type, the structure of a DLchannel monitored by the UE may be different. For example, the DLchannel to be monitored may be shared among multiple users (e.g., astructure similar to the RAR of Msg2) or a DL channel to be monitoredmay be configured for each user (e.g., an (N)PDCCH/MPDCCH of a USS).When a DL channel is defined independently for each user, a CQI isreported on a user basis. On the contrary, in the case where multipleusers share and decode a DL channel, when user information exists foreach individual user or for each group, only a specific user may beconfigured to report a CQI. This is because the channel should bescheduled based on the reception performance of a UE with the worst ofthe DL channel qualities of users sharing the DL channel. Further, theBS may configure a CQI to be reported only when a specific condition isor is not satisfied. The specific condition may mean, for example, thata CQI measured by a UE is less than a specific value. The CQI may bedifferent from a CQI for the initial access procedure. A referencechannel required to derive a CQI may be defined according to a PUR typeand/or a DL channel. Further, when a PUR is configured for the UE in theRRC connected mode, the UE may be configured to report a CQI in a PUR inthe RRC idle mode only as a delta value from the existing CQI based onsome attribute of DL channel parameters because the BS may have alreadyhad DL channel quality information and thus have configured DL channelparameters based on the DL channel quality information.

{circle around (3)} In the case of CQI transmission in a PUR, the CQImay be defined as the repetition number and/or AL of the (N)PDCCH orMPDCCH, rather than it is defined based on the PDSCH regardless of theCE mode.

2) CQI measurement time

A. CQI measurement and reporting may be performed only when DL receptionis required to determine whether to continue PUR transmission, not inevery PUR transmission unit. That is, only when an operation ofdetermining whether a configured PUR is still valid in consideration ofa change in an ambient environment of the UE is performed, such anoperation may be restrictively required.

F.16 Method of Reporting CQI of Control Channel in RRC Connected Mode

The present disclosure proposes a method of reporting the CQI of a DLcontrol channel (e.g., MPDCCH, NPDCCH, or PDSCH) by a UE, which may beapplied irrespective of the RRC states. However, a control channel thatthe UE attempts to detect in the RRC connected mode may be differentfrom a control channel that the UE attempts to detect in the RRC idlemode. Accordingly, a CQI may be measured and reported in differentmethods in the RRC connected mode and the RRC idle mode. In thissection, a series of procedures related to the method of reporting theCQI of a DL control channel in the RRC_CONNECTED mode are proposed.While the proposed method is described in the context of an MPDCCH in aneMTC system for the convenience of explanation, it may also be appliedto other communication systems such as NB-IoT, LTE, and NR. Specificexamples and channel/signal names in the proposed method may beinterpreted as examples and channel/signal names intended to serve thesame/similar purpose in the corresponding other systems.

1) Reference MPDCCH format for measuring CQI

A. Unlike the RRC idle mode, the UE may monitor an MPDCCH in a USSconfigured on a UE basis in the RRC connected mode. Considering thateven though each UE monitors the same DCI format (e.g., DCI formats 6-0Aand 6-1A or DCI formats 6-0B and 6-1B), the DCI size of a USS may bedifferent according to a UE capability (e.g., sub-PRB, 64 QAM, orwideband support or non-support), a CQI may be measured/calculated in adifferent reference channel (e.g., hypothetical MPDCCH). Further,because a UE in CE Mode A may monitor not only a USS but also aTypeO-CSS in the RRC connected mode, a reference format for CQImeasurement (and/or a search space type-only for CE mode A) may beconfigured by the BS or defined by a specific agreement. That is, evenfor the same UE, the size of the reference format may be changedaccording to parameter information configured for the USS with referenceto the capability of the UE by the BS.

B. An ECCE is an MPDCCH allocation unit. A minimum number of ECCEsincluded in an MPDCCH may be different in each subframe carrying theMPDCCH, and thus the reference for a CQI may vary. That is, when the CQIis a value representing the repetition number and/or AL of the MPDCCH(e.g., a value that may satisfy a specific criterion for hypotheticalMPDCCH reception detection performance), a reference MPDCCH format fromwhich the CQI is derived (e.g., see TS36.211 Table 6.8B.1-2) may be“indicated by the BS”, “fixed in the standard”, or “fixed and signaledat a time when an MPDCCH triggering CQI reporting (an MPDCCH indicatingCQI reporting in an aperiodic CQI triggering manner) is received or at arelative time from the time.

2) CQI information configuration

A. When a “maximum repetition number Rmax configured for the searchspace of a reference MPDCCH format (a maximum number of times an MPDCCHmay be repeated in the search space) or a maximum value which may bereported in a CQI (e.g., an MPDCCH repetition number required for the UEto detect a hypothetical MPDCCH with performance equal to or higher thanspecific reference performance) (referred to as B) is less than “thenumber of hopping NBs used for MPDCCH transmission x an availablerepetition number for an MPDCCH subframe in each hop)” (referred to asA), as much resources as A may be divided into resource parts eachcorresponding to a size B, a CQI may be derived for each resource part,and the worst (or best) CQI (e.g., lowest (or highest) in terms ofefficiency) may be selected as a representative CQI. Information aboutthe resource part based on which the CQI has been derived may also beincluded in the CQI.

B. Since a USS may be configured on a UE basis, each UE may include, ina CQI, its preferred MPDCCH or USS configuration (e.g., a configurationby which MPDCCH detection performance satisfies specific referenceperformance by using minimum resources) among various available MPDCCHor USS configurations, and report the CQI to the BS. The BS may changeMPDCCH configuration information of the UE by reflecting the CQI. Thefollowing information may be included in the preferred MPDCCH or USSconfiguration.

{circle around (1)} MPDCCH resource mapping scheme (e.g., distributedmapping or localized mapping)

{circle around (2)} MPDCCH hopping enable/disable information(characteristically, this information may be restrictively included inthe CQI, only when the MPDCCH hopping configuration is enabled at a timeof triggering MPDCCH CQI reporting).

{circle around (3)}When there are two or more MPDCCH PRB sets (e.g., seeTS36.213 Table 9.1.5-1a, Table 9.1.5-1b, Table 9.1.5-2a, and Table9.1.5-2b), information about an assumed PRB set or a UE-preferred MPDCCHPRB set in deriving a CQI.

3) Additional features when the relationship between a CRS port and anMPDCCH DMRS port is used

The MPDCCH is transmitted by the same precoding as used for a DMRS portrelated to an ECCE included in the MPDCCH. Precoding information appliedto a corresponding DMRS based on a CRS is generally not provided to theUE. If all or some of the above information may be additionally providedfor the purpose of, for example, improvement of MPDCCH detectionperformance, the UE may additionally report related information (e.g.,the relationship between an MPDCCH DMRS port and a CRS port) to the BS,together with or separately from the CQI.

A. When precoder information about the CRS and DMRS ports may be fixedto a specific value or cycled in every specific time/frequency unit, theUE may report UE-preferred precoding information (e.g., which mayinclude information indicating that cycling is preferred or informationrequesting use of a specific precoder or cycling in a specific way).Further, the BS may indicate a precoder relationship between assumed CRSand DMRS ports, when the UE derives an MPDCCH CQI. Obviously, theinformation may be for indicating assumption of a specific precoder, ormay indicate that it is not necessary to assume a specific precodercombination.

B. The UE may be configured to assume precoder information (e.g, a PMI)included in the most recent CSI report for a PDSCH (or the most recentCSI report for the PDSCH before a specific time) as precoder informationto be assumed when the UE calculates an MPDCCH CQI (e.g., the repetitionnumber and/or AL of the hypothetical MPDCCH).

F.17 Flowcharts of Operations According to the Proposals of the PresentDisclosure

FIG. 14 is a flowchart illustrating a method of transmitting (orreporting) information regarding DQI in Msg1 to a BS by a UE. Theexample of FIG. 14 may be performed by the UE in the RRC_IDLE state orthe RRC CONNECTED state. In the description of FIG. 14, (RA-0) to (RA-4)refer to the random access procedure described in section F. Asdescribed before, the term UE may be replaced with the terms userequipment, MS, UT, SS, MT, and wireless device.

In step S102, the UE may receive random access related configurationinformation through system information (or an SIB) from the BS. Forexample, step S102 may correspond to step (RA-0). Accordingly, the UEmay receive the system information (or SIB) including the random accessrelated configuration information according to the operation describedin relation to step (RA-0) and/or the operation proposed in the presentdisclosure (e.g., see section F.1 to section F.16).

In step S104, the UE may transmit a random access preamble (or Msg1) tothe BS based on the received configuration information. For example,step S104 may correspond to step (RA-1). In step S104, the UE mayfurther transmit information regarding DQI through the random accesspreamble to the BS according to the present disclosure. To transmit theinformation regarding DQI through the random access preamble, theoperation described in section F.1, and/or the operation proposed in thepresent disclosure (e.g., see section F.2 to section F.16).

After step S104, the UE may perform the same operations as steps (RA-2),(RA-3), and (RA-4).

FIG. 15 is a flowchart illustrating a method of receiving (or receivinga report of) information regarding DQI in Msg1 from a UE by a BS. In theexample of FIG. 15, the BS may perform the method with a UE in anRRC_IDLE state or an RRC CONNECTED state. In the description of FIG. 15,step (RA-0) to step (RA-4) refer to the random access proceduredescribed in section F. As described above, a BS is a wireless devicethat communicates with a UE and the term BS is interchangeably used withother terms such as eNB, gNB, BTS, and AP.

In step S202, the BS may transmit random access related configurationinformation through system information (or an SIB) to the UE. Forexample, step S202 may correspond to step (RA-0). Accordingly, the BSmay transmit to the UE the system information (or SIB) including therandom access related configuration information according to theoperation described in relation to step (RA-0) and/or the operationproposed in the present disclosure (e.g., see section F.1 to sectionF.16).

In step S204, the BS may receive a random access preamble (or Msg1) fromthe UE based on the transmitted configuration information. For example,step S204 may correspond to step (RA-1). In step S204, the BS mayfurther receive information regarding DQI through the random accesspreamble from the UE according to the present disclosure. To receive theinformation regarding DQI through the random access preamble, the BS mayperform the operation described in relation to step (RA-1), theoperation described in section F.1, and/or the operation proposed in thepresent disclosure (e.g., see section F.2 to section F.16).

After step S204, the BS may perform the same processes as steps (RA-2),(RA-3), and (RA-4).

As described above, the UE may provide the DQI in step (RA-3) so thatthe BS may use the DQI for DL scheduling in step (RA-4).

FIG. 16 is a flowchart illustrating a method of transmitting (orreporting) information regarding DQI in Msg3 to a BS by a UE. Theexample of FIG. 16 may be performed by a UE in an RRC_IDLE state or anRRC_CONNECTED state. In the description of FIG. 16, step (RA-0) to step(RA-4) refer to the random access procedure described in section F. Asdescribed above, the term UE is interchangeably used with other termssuch as user equipment, MS, UT, SS, MT, and wireless device.

In step S302, the UE may transmit a random access preamble (or Msg1) tothe BS. For example, step S302 may correspond to step (RA-1).Accordingly, the UE may transmit the random access preamble to the BSaccording to the operation of step (RA-1) and/or the operation proposedin the present disclosure. A configuration for the random accesspreamble transmission may be preset according to the operation of step(RA-0) and/or the operation proposed in the present disclosure (e.g.,see section F.1 to section F.16). For example, an operationcorresponding to step (RA-0) may be performed before step S302 (notshown), and reporting of information regarding DCI through Msg3 may beenabled based on system information broadcast by the BS.

In step S304, the UE may receive an RAR (or Msg2) from the BS inresponse to the transmitted random access preamble (or Msg1). Forexample, step S304 may correspond to step (RA-2), and the RAR mayinclude information described herein and/or information proposed by thepresent disclosure. The UE may receive the RAR from the BS according tothe operation of step (RA-2) and/or the operation proposed in thepresent disclosure (e.g., see section F.1 to section F.16). For example,the RAR may include an indication (or information) indicating the UE toreport information regarding the DQI through Msg3.

In step S306, the UE may transmit a message for contention resolution(or Msg3) to the BS on a physical UL channel (e.g., PUSCH or NPUSCH)based on the received RAR (or Msg2). For example, step S306 maycorrespond to step (RA-3). In step S306, the UE may further transmit theinformation regarding DQI through the physical UL channel (e.g., PUSCHor NPUSCH) (or through the message for contention resolution) to the BSaccording to the present disclosure. To this end, the physical ULchannel (e.g., PUSCH or NPUSCH) (or the message for contentionresolution) may include information described herein and/or informationproposed by the present disclosure. The UE may transmit informationregarding the DQI through the physical uplink channel (e.g., PUSCH orNPUSCH) (or through the message for contention resolution) according tothe operation of step (RA-3) and/or the operation proposed in thepresent disclosure (e.g., see section F.1 to section F.16). For example,information regarding the DQI may be transmitted to the BS through ahigher-layer signal (e.g., a MAC message or an RRC message).

After step S306, the UE may perform the same process as in step (RA-4).

FIG. 17 is a flowchart illustrating a method of receiving (a report of)information regarding DQI through Msg 3 from a UE. In the example ofFIG. 17, the BS may perform the method with the UE in an RRC_IDLE stateor an RRC_CONNECTED state. In the description of FIG. 17, step (RA-0) tostep (RA-4) refer to the random access procedure described in section F.As described above, a BS is a wireless device that communicates with aUE, and the term BS is interchangeably used with other terms such aseNB, gNB, BTS, and AP.

In step S402, the BS may receive a random access preamble (or Msg1) fromthe UE. For example, step S402 may correspond to step (RA-1).Accordingly, the BS may receive the random access preamble from the UEaccording to the operation of step (RA-1) and/or the operation proposedin the present disclosure. A configuration for the random accesspreamble transmission may be preset according to the operation of step(RA-0) and/or the operation proposed in the present disclosure (e.g.,see section F.1 to section F.16).

In step S404, the BS may transmit an RAR (or Msg2) to the UE in responseto the received random access preamble (or Msg1). For example, step S404may correspond to step (RA-2), and the RAR may include informationdescribed herein and/or information proposed in the present disclosure.The BS may transmit the RAR to the UE according to the operation of step(RA-2) and/or the operation proposed in the present disclosure (e.g.,see section F.1 to section F.16).

In step S406, the BS receives a message for contention resolution (orMsg3) through a physical UL channel (e.g., PUSCH or NPUSCH) from the UEin response to the transmitted RAR (or Msg2). For example, step S406 maycorrespond to step (RA-3). In step S406, the BS may further receiveinformation regarding the DQI through the physical UL channel (e.g.,PUSCH or NPUSCH) (or through the message for contention resolution) fromthe UE according to the present disclosure. To this end, the physical ULchannel (e.g., PUSCH or NPUSCH) (or the message for contentionresolution) may include information described herein and/or informationproposed in the present disclosure. The BS may receive the informationregarding DQI through the physical UL channel (e.g., PUSCH or NPUSCH)(or through the message for contention resolution) from the UE accordingto the operation of step (RA-3) and/or the operation proposed in thepresent disclosure (e.g., see section F.1 to section F.16).

After step S406, the BS may perform the same process as in step (RA-4).

In the examples of FIGS. 14 to 17, the operations described hereinand/or the operations proposed in the present disclosure (e.g., seesection F.1 to section F.16) may be performed in combination with the UEoperations or the BS operations without limitation. All of the contentsof “F. Proposed Methods of the Present Disclosure” are incorporated byreference in the descriptions of FIGS. 14 to 17.

By way of a non-limiting example, as proposed in the present disclosure,DQI may include RSRP and/or RSRQ information, a repetition number Rand/or an AL related to actual PDCCH (MPDCCH or NPDCCH) decoding, arepetition number R and/or an AL related to hypothetical PDCCH (MPDCCHor NPDCCH) decoding, a repetition number R related to actual PDSCH (orNPDSCH) decoding, a repetition number R related to hypothetical PDSCH(or NPDSCH) decoding, a CQI, or a combination of at least two thereof(e.g., see sections F.1.1, F.6, F.7, F.9, and F.10).

In a more specific example, as proposed in the present disclosure, theDQI may include information representing the repetition number of aphysical DL control channel (e.g., PDCCH, 1VIPDCCH, or NPDCCH) relatedto an RAR at a time of detecting the physical DL control channel. Inthis example, the DQI may further include information representing theAL of the physical DL control channel (e.g., PDCCH, MPDCCH, or NPDCCH)related to the RAR at the time of detecting the physical DL controlchannel. Alternatively, when the repetition number of the physical DLcontrol channel has a value satisfying a specific performancerequirement, the DQI may be transmitted on the assumption that the AL ofthe physical DL control channel related to the RAR is a reference AL(e.g., 24), and the specific performance requirement may include therepetition number of the physical DL control channel being 1.

In another specific example, as proposed in the present disclosure, theDQI may include information about a repetition number required to detecta hypothetical physical DL control channel at a specific BLER, and thespecific BLER may be, for example, 1%. In this example, the DQI mayfurther include information about an AL required to detect thehypothetical physical DL control channel at the specific BLER.Alternatively, when the repetition number required to detect thehypothetical physical DL control channel satisfies a specificperformance requirement, the DQI may be transmitted on the assumptionthat the AL of the hypothetical physical DL control channel is areference AL (e.g., 24), and the specific performance requirement mayinclude the repetition number required to detect the hypotheticalphysical DL control channel being 1.

As described before, the random access procedures illustrated in FIGS.14 to 17 may be performed when the UE is in the RRC_IDLE state or theRRC_CONNECTED state. By way of a non-limiting example, in the RRC_IDLEstate, the EE may perform a random access procedure for initial accessor for EDT (see sections F.1, F.4, F.5, F.6, F.7, F.9, F.13, F.15 and F.16). In this example, when a random access preamble is transmitted inthe RRC_IDLE state, DQI may be measured based on a CC (e.g., Type 2 CSS)for receiving an RAR (or Msg2). More specifically, the DQI may bedetermined based on a maximum repetition number Rmax configured for theCC (e.g., Type 2 CSS) for receiving the RAR (or Msg2). Alternatively, byway of a non-limiting example, in the RRC CONNECTED state, the UE mayperform a random access procedure based on an (N)PDCCH order or forrequesting resource scheduling (see sections F.1, F.5, F.6, F.7, F.13,F.14, F.15 and F. 16). In this example, when a random access preamble istransmitted based on an (N)PDCCH order or for requesting resourcescheduling in the RRC CONNECTED state, DQI may be measured based on aUSS configured in the RRC CONNECTED state (e.g., a maximum repetitionnumber Rmax configured for the USS) or based on a repetition numberrequired to detect a hypothetical physical DL control channel at aspecific BLER (e.g., 1%).

While the present disclosure has been described above in relation to therandom access procedures, the present disclosure may also be applied inthe same/similar manner when DQI is measured/reported in anRRC_CONNECTED state, not limited to the random access procedures.

G. Communication System and Devices to Which the Present Disclosure isApplied

Various descriptions, functions, procedures, proposals, methods, and/oroperation flowcharts of the present disclosure described herein may beapplied to, but not limited to, various fields requiring wirelesscommunication/connection (e.g., 5G) between devices.

The communication system and devices will be described in detail withreference to the drawings. Unless otherwise specified, like referencenumerals denote the same or corresponding hardware blocks, softwareblocks, or functional blocks in the drawings/description.

FIG. 18 illustrates a block diagram of a wireless communicationapparatus to which the methods proposed in the present disclosure areapplicable.

Referring to FIG. 18, a wireless communication system includes a BS 10and multiple UEs 20 located within coverage of the BS 10. The BS 10 andthe UE may be referred to as a transmitter and a receiver, respectively,and vice versa. The BS 10 includes a processor 11, a memory 14, at leastone Tx/Rx radio frequency (RF) module (or RF transceiver) 15, a Txprocessor 12, an Rx processor 13, and an antenna 16. The UE 20 includesa processor 21, a memory 24, at least one Tx/Rx RF module (or RFtransceiver) 25, a Tx processor 22, an Rx processor 23, and an antenna26. The processors are configured to implement the above-describedfunctions, processes and/or methods. Specifically, the processor 11provides a higher layer packet from a core network for DL transmission(communication from the BS to the UE). The processor implements thefunctionality of layer 2 (L2). In DL, the processor provides the UE 20with multiplexing between logical and transmission channels and radioresource allocation. That is, the processor is in charge of signaling tothe UE. The Tx processor 12 implements various signal processingfunctions of layer 1 (L1) (i.e., physical layers). The signal processingfunctions include facilitating the UE to perform forward errorcorrection (FEC) and performing coding and interleaving. Coded andmodulated symbols may be divided into parallel streams. Each stream maybe mapped to an OFDM subcarrier, multiplexed with an RS in the timeand/or frequency domain, and then combined together using an inversefast Fourier transform (IFFT) to create a physical channel carrying atime domain OFDMA symbol stream. The OFDM stream is spatially precodedto produce multiple spatial streams. Each spatial stream may be providedto a different antenna 16 through the Tx/Rx module (or transceiver) 15.Each Tx/Rx module may modulate an RF carrier with each spatial streamfor transmission. At the UE, each Tx/Rx module (or transceiver) 25receives a signal through each antenna 26 thereof. Each Tx/Rx modulerecovers information modulated on the RF carrier and provides theinformation to the RX processor 23. The Rx processor implements varioussignal processing functions of layer 1. The Rx processor may performspatial processing on the information to recover any spatial streamstoward the UE. If multiple spatial streams are destined for the UE, themultiple spatial streams may be combined by multiple Rx processors intoa single OFDMA symbol stream. The RX processor converts the OFDMA symbolstream from the time domain to the frequency domain using a fast Fouriertransform (FFT). A frequency-domain signal includes a separate OFDMAsymbol stream for each subcarrier of an OFDM signal. The symbols and thereference signal on each subcarrier are recovered and demodulated bydetermining the most probable signal constellation points transmitted bythe BS. Such soft decisions may be based on channel estimation values.The soft decisions are decoded and deinterleaved to recover data andcontrol signals originally transmitted by the BS over the physicalchannel. The corresponding data and control signals are provided to theprocessor 21.

UL transmission (communication from the UE to the BS) is processed bythe BS10 in a similar way to that described in regard to the receiverfunctions of the UE 20. Each Tx/Rx module (or transceiver) 25 receives asignal through each antenna 26. Each Tx/Rx module provides an RF carrierand information to the Rx processor 23. The processor 21 may beconnected to the memory 24 storing program codes and data. The memorymay be referred to as a computer-readable medium.

The present disclosure described above may be carried out by the BS 10and the UE 20 which are wireless communication devices illustrated inFIG. 18.

FIG. 19 illustrates a communication system 1 applied to the presentdisclosure.

Referring to FIG. 19, the communication system 1 applied to the presentdisclosure includes wireless devices, BSs, and a network. The wirelessdevices refer to devices performing communication by radio accesstechnology (RAT) (e.g., 5G New RAT (NR) or LTE), which may also becalled communication/radio/5G devices. The wireless devices may include,but no limited to, a robot 100 a, vehicles 100 b-1 and 100 b-2, anextended reality (XR) device 100 c, a hand-held device 100 d, a homeappliance 100 e, an IoT device 100 f, and an artificial intelligence(AI) device/server 400. For example, the vehicles may include a vehicleequipped with a wireless communication function, an autonomous drivingvehicle, and a vehicle capable of performing vehicle-to-vehicle (V2V)communication. The vehicles may include an unmanned aerial vehicle (UAV)(e.g., a drone). The XR device may include an augmented reality(AR)/virtual reality (VR)/mixed reality (MR) device, and may beimplemented in the form of a head-mounted device (HMD), a head-updisplay (HUD) mounted in a vehicle, a television (TV), a smartphone, acomputer, a wearable device, a home appliance, a digital signage, avehicle, a robot, and so on. The hand-held device may include asmartphone, a smartpad, a wearable device (e.g., a smartwatch or smartglasses), and a computer (e.g., a laptop). The home appliance mayinclude a TV, a refrigerator, and a washing machine. The IoT device mayinclude a sensor and a smart meter. For example, the BSs and the networkmay be implemented as wireless devices, and a specific wireless device200 a may operate as a BS/network node for other wireless devices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f, and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured by using a 3G network, a 4G (e.g., LTE) network, or a 5G(e.g., NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without intervention of theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. V2V/vehicle-to-everything (V2X)communication). The IoT device (e.g., a sensor) may perform directcommunication with other IoT devices (e.g., sensors) or other wirelessdevices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f and the BSs 200,or between the BSs 200. Herein, the wireless communication/connectionsmay be established through various RATs (e.g., 5G NR) such as UL/DLcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter-BS communication 150 c (e.g. relay, integratedaccess backhaul (IAB)). A wireless device and a BS/a wireless devices,and BSs may transmit/receive radio signals to/from each other throughthe wireless communication/connections 150 a, 150 b, and 150 c. To thisend, at least a part of various configuration information configuringprocesses, various signal processing processes (e.g., channelencoding/decoding, modulation/demodulation, and resourcemapping/demapping), and resource allocating processes, fortransmitting/receiving radio signals, may be performed based on thevarious proposals of the present disclosure.

FIG. 20 illustrates wireless devices applicable to the presentdisclosure.

Referring to FIG. 20, a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless devices 100 a to100 f and the BSs 200} and/or {the wireless devices 100 a to 100 f andthe wireless devices 100 a to 100 f} of FIG. 19.

The first wireless device 100 may include at least one processor 102 andat least one memory 104, and may further include at least onetransceiver 106 and/or at least one antenna 108. The processor 102 maycontrol the memory 104 and/or the transceiver 106 and may be configuredto implement the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Forexample, the processor 102 may process information within the memory 104to generate first information/signal and then transmit a radio signalincluding the first information/signal through the transceiver 106. Theprocessor 102 may receive a radio signal including secondinformation/signal through the transceiver 106 and then storeinformation obtained by processing the second information/signal in thememory 104. The memory 104 may be coupled to the processor 102 and storevarious types of information related to operations of the processor 102.For example, the memory 104 may store software code including commandsfor performing a part or all of processes controlled by the processor102 or for performing the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. Herein, the processor 102 and the memory 104 may be a part ofa communication modem/circuit/chip designed to implement an RAT (e.g.,LTE or NR). The transceiver 106 may be coupled to the processor 102 andtransmit and/or receive radio signals through the at least one antenna108. The transceiver 106 may include a transmitter and/or a receiver.The transceiver 106 may be interchangeably used with an RF unit. In thepresent disclosure, a wireless device may refer to a communicationmodem/circuit/chip.

The second wireless device 200 may include at least one processor 202and at least one memory 204, and may further include at least onetransceiver 206 and/or at least one antenna 208. The processor 202 maycontrol the memory 204 and/or the transceiver 206 and may be configuredto implement the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Forexample, the processor 202 may process information within the memory 204to generate third information/signal and then transmit a radio signalincluding the third information/signal through the transceiver 206. Theprocessor 202 may receive a radio signal including fourthinformation/signal through the transceiver 206 and then storeinformation obtained by processing the fourth information/signal in thememory 204. The memory 204 may be coupled to the processor 202 and storevarious types of information related to operations of the processor 202.For example, the memory 204 may store software code including commandsfor performing a part or all of processes controlled by the processor202 or for performing the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. Herein, the processor 202 and the memory 204 may be a part ofa communication modem/circuit/chip designed to implement an RAT (e.g.,LTE or NR). The transceiver 206 may be coupled to the processor 202 andtransmit and/or receive radio signals through the at least one antenna208. The transceiver 206 may include a transmitter and/or a receiver.The transceiver 206 may be interchangeably used with an RF unit. In thepresent disclosure, a wireless device may refer to a communicationmodem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described in greater detail. One or more protocol layers may beimplemented by, but not limited to, one or more processors 102 and 202.For example, the one or more processors 102 and 202 may implement one ormore layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC,and SDAP). The one or more processors 102 and 202 may generate one ormore protocol data units (PDUs) and/or one or more service data units(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented in hardware,firmware, software, or a combination thereof. For example, one or moreapplication specific integrated circuits (ASICs), one or more digitalsignal processors (DSPs), one or more digital signal processing devices(DSPDs), one or more programmable logic devices (PLDs), or one or morefield programmable gate arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented in firmware or software, which may beconfigured to include modules, procedures, or functions. Firmware orsoftware configured to perform the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be included in the one or more processors 102 and 202, ormay be stored in the one or more memories 104 and 204 and executed bythe one or more processors 102 and 202. The descriptions, functions,procedures, proposals, methods, and/or operational flowcharts disclosedin this document may be implemented as code, instructions, and/or a setof instructions in firmware or software.

The one or more memories 104 and 204 may be coupled to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured as read-onlymemories (ROMs), random access memories (RAMs), electrically erasableprogrammable read-only memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be coupled to theone or more processors 102 and 202 through various technologies such aswired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe coupled to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may control the one or more transceivers 106 and 206 to transmituser data, control information, or radio signals to one or more otherdevices. The one or more processors 102 and 202 may control the one ormore transceivers 106 and 206 to receive user data, control information,or radio signals from one or more other devices. The one or moretransceivers 106 and 206 may be coupled to the one or more antennas 108and 208 and configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 21 illustrates another example of wireless devices applied to thepresent disclosure. The wireless devices may be implemented in variousforms according to use-cases/services (refer to FIG. 19).

Referring to FIG. 21, wireless devices 100 and 200 may correspond to thewireless devices 100 and 200 of FIG. 20 and may be configured as variouselements, components, units/portions, and/or modules. For example, eachof the wireless devices 100 and 200 may include a communication unit110, a control unit 120, a memory unit 130, and additional components140. The communication unit may include a communication circuit 112 andtransceiver(s) 114. For example, the communication circuit 112 mayinclude the one or more processors 102 and 202 and/or the one or morememories 104 and 204 of FIG. 20. For example, the transceiver(s) 114 mayinclude the one or more transceivers 106 and 206 and/or the one or moreantennas 108 and 208 of FIG. 20. The control unit 120 is electricallycoupled to the communication unit 110, the memory unit 130, and theadditional components 140 and provides overall control to operations ofthe wireless devices. For example, the control unit 120 may control anelectric/mechanical operation of the wireless device based onprograms/code/commands/information stored in the memory unit 130. Thecontrol unit 120 may transmit the information stored in the memory unit130 to the outside (e.g., other communication devices) via thecommunication unit 110 through a wireless/wired interface or store, inthe memory unit 130, information received through the wireless/wiredinterface from the outside (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be configured in various mannersaccording to the types of wireless devices. For example, the additionalcomponents 140 may include at least one of a power unit/battery, aninput/output (I/O) unit, a driver, and a computing unit. The wirelessdevice may be configured as, but not limited to, the robot (100 a ofFIG. 19), the vehicles (100 b-1 and 100 b-2 of FIG. 19), the XR device(100 c of FIG. 19), the hand-held device (100 d of FIG. 19), the homeappliance (100 e of FIG. 19), the IoT device (100 f of FIG. 19), adigital broadcasting terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a FinTech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 19), the BSs (200 of FIG. 19), a networknode, etc. The wireless device may be mobile or fixed according to ause-case/service.

In FIG. 21, all of the various elements, components, units/portions,and/or modules in the wireless devices 100 and 200 may be coupled toeach other through a wired interface or at least a part thereof may bewirelessly coupled to each other through the communication unit 110. Forexample, in each of the wireless devices 100 and 200, the control unit120 and the communication unit 110 may be coupled wiredly, and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslycoupled through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured as a set of one or more processors. For example, thecontrol unit 120 may be configured as a set of a communication controlprocessor, an application processor, an electronic control unit (ECU), agraphical processing unit, and a memory control processor. In anotherexample, the memory unit 130 may be configured as a random access memory(RAM), a dynamic RAM (DRAM), a read only memory (ROM), a flash memory, avolatile memory, a non-volatile memory, and/or a combination thereof.

An implementation example of FIG. 21 will be described in detail withreference to the drawings.

FIG. 22 illustrates a portable device applied to the present disclosure.The portable device may include a smartphone, a smartpad, a wearabledevice (e.g., a smart watch and smart glasses), and a portable computer(e.g., a laptop). The portable device may be referred to as a mobilestation (MS), a user terminal (UT), a mobile subscriber station (MSS), asubscriber station (SS), an advanced mobile station (AMS), or a wirelessterminal (WT).

Referring to FIG. 22, a portable device 100 may include an antenna unit108, a communication unit 110, a control unit 120, a power supply unit140 a, an interface unit 140 b, and an I/O unit 140 c. The antenna unit108 may be configured as a part of the communication unit 110. Theblocks 110 to 130/140 a to 140 c correspond to the blocks 110 to 130/140of FIG. 21, respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from another wireless device and a BS. Thecontrol unit 120 may perform various operations by controlling elementsof the portable device 100. The control unit 120 may include anapplication processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands required for operation of theportable device 100. Further, the memory unit 130 may store input/outputdata/information. The power supply unit 140 a may supply power to theportable device 100, and include a wired/wireless charging circuit and abattery. The interface unit 140 b may include various ports (e.g., anaudio I/O port and a video I/O port) for connectivity to externaldevices The I/O unit 140 c may acquire information/signals (e.g., touch,text, voice, images, and video) input by a user, and store the acquiredinformation/signals in the memory unit 130. The communication unit 110may receive or output video information/signal, audioinformation/signal, data, and/or information input by the user. The I/Ounit 140 c may include a camera, a microphone, a user input unit, adisplay 140 d, a speaker, and/or a haptic module.

For example, for data communication, the I/O unit 140 c may acquireinformation/signals (e.g., touch, text, voice, images, and video)received from the user and store the acquired information/signal sin thememory unit 130. The communication unit 110 may convert theinformation/signals to radio signals and transmit the radio signalsdirectly to another device or to a BS. Further, the communication unit110 may receive a radio signal from another device or a BS and thenrestore the received radio signal to original information/signal. Therestored information/signal may be stored in the memory unit 130 andoutput in various forms (e.g., text, voice, an image, video, and ahaptic effect) through the I/O unit 140 c.

FIG. 23 illustrates a vehicle or an autonomous driving vehicle appliedto the present disclosure. The vehicle or autonomous driving vehicle maybe configured as a mobile robot, a car, a train, a manned/unmannedaerial vehicle (AV), a ship, or the like.

Referring to FIG. 23, a vehicle or autonomous driving vehicle 100 mayinclude an antenna unit 108, a communication unit 110, a control unit120, a driving unit 140 a, a power supply unit 140 b, a sensor unit 140c, and an autonomous driving unit 140 d. The antenna unit 108 may beconfigured as a part of the communication unit 110. The blocks110/130/140 a to 140 d correspond to the blocks 110/130/140 of FIG. 21,respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous driving vehicle 100. The control unit 120 mayinclude an ECU. The driving unit 140 a may enable the vehicle or theautonomous driving vehicle 100 to travel on a road. The driving unit 140a may include an engine, a motor, a powertrain, a wheel, a brake, asteering device, and so on. The power supply unit 140 b may supply powerto the vehicle or the autonomous driving vehicle 100 and include awired/wireless charging circuit, a battery, and so on. The sensor unit140 c may acquire vehicle state information, ambient environmentinformation, user information, and so on. The sensor unit 140 c mayinclude an inertial measurement unit (IMU) sensor, a collision sensor, awheel sensor, a speed sensor, a slope sensor, a weight sensor, a headingsensor, a position module, a vehicle forward/backward sensor, a batterysensor, a fuel sensor, a tire sensor, a steering sensor, a temperaturesensor, a humidity sensor, an ultrasonic sensor, an illumination sensor,a pedal position sensor, and so on. The autonomous driving unit 140 dmay implement a technology for maintaining a lane on which a vehicle isdriving, a technology for automatically adjusting speed, such asadaptive cruise control, a technology for autonomously traveling along adetermined path, a technology for traveling by automatically setting apath, when a destination is set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, and so on from an external server. The autonomousdriving unit 140 d may generate an autonomous driving path and a drivingplan from the obtained data. The control unit 120 may control thedriving unit 140 a such that the vehicle or autonomous driving vehicle100 may move along the autonomous driving path according to the drivingplan (e.g., speed/direction control). In the middle of autonomousdriving, the communication unit 110 may aperiodically/periodicallyacquire recent traffic information data from the external server andacquire surrounding traffic information data from neighboring vehicles.In the middle of autonomous driving, the sensor unit 140 c may obtainvehicle state information and/or ambient environment information. Theautonomous driving unit 140 d may update the autonomous driving path andthe driving plan based on the newly obtained data/information. Thecommunication unit 110 may transmit information about a vehicleposition, the autonomous driving path, and/or the driving plan to theexternal server. The external server may predict traffic informationdata using AI technology or the like, based on the information collectedfrom vehicles or autonomous driving vehicles and provide the predictedtraffic information data to the vehicles or the autonomous drivingvehicles.

The embodiments of the present disclosure described hereinbelow arecombinations of elements and features of the present disclosure. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent disclosure may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent disclosure may be rearranged. Some constructions or features ofany one embodiment may be included in another embodiment and may bereplaced with corresponding constructions or features of anotherembodiment. It is obvious to those skilled in the art that claims thatare not explicitly cited in each other in the appended claims may bepresented in combination as an embodiment of the present disclosure orincluded as a new claim by a subsequent amendment after the applicationis filed.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to wireless communication devicessuch as a user equipment (UE) and a BS (BS) operating in variouswireless communication systems including 3GPP LTE/LTE-A/5G (or New RAT(NR)).

The invention claimed is:
 1. A method of transmitting channel qualityinformation to a base station (BS) by a user equipment (UE) in awireless communication system supporting narrowband Internet of things(NB-IoT), the method comprising: transmitting a random access preambleto the BS; receiving a random access response from the BS; andtransmitting the channel quality information to the BS through anarrowband physical uplink shared channel (NPUSCH) based on the randomaccess response, wherein the channel quality information is related to arepetition number required to detect a hypothetical narrowband physicaldownlink control channel (NPDCCH) at a 1% block error rate (BLER),wherein the required repetition number is represented based on a maximumNPDCCH repetition number ‘R_(max)’ for the random access responsereception, and wherein a maximum value which can be used as the requiredrepetition number for the hypothetical NPDCCH, is K times larger thanthe maximum NPDCCH repetition number ‘R_(max)’ for the random accessresponse reception.
 2. The method according to claim 1, wherein themaximum NPDCCH repetition number ‘R_(max)’ is configured in the UEthrough system information transmitted by the BS.
 3. The methodaccording to claim 1, wherein the random access preamble is transmittedin an RRC idle state, and the channel quality information is measuredbased on a common search space (CSS) used to receive the random accessresponse.
 4. The method according to claim 1, wherein a first value isavailable for the UE as the required repetition number for thehypothetical NPDCCH, where the first value is larger than ‘R_(max)’, butnot exceeding the maximum value.
 5. The method according to claim 1,wherein the channel quality information is measured for a non-anchorcarrier.
 6. A non-transitory computer readable medium recorded thereoninstructions for performing the method of claim
 1. 7. A user equipment(UE) configured to transmit channel quality information to a basestation (BS) in a wireless communication system supporting narrowbandInternet of things (NB-IoT), the UE comprising: a radio frequency (RF)transceiver; and a processor operatively coupled to the RF transceiver,wherein the processor is configured to transmit a random access preambleto the BS, receive a random access response from the BS, and transmitthe channel quality information to the BS through a narrowband physicaluplink shared channel (NPUSCH) based on the random access response, bycontrolling the RF transceiver, and wherein the channel qualityinformation is related to a repetition number required to detect anarrowband physical downlink control channel (NPDCCH) at a 1% blockerror rate (BLER), wherein the required repetition number is representedbased on a maximum NPDCCH repetition number ‘R_(max)’ for the randomaccess response reception, and wherein a maximum value which can be usedas the required repetition number for the hypothetical NPDCCH, is Ktimes larger than the maximum NPDCCH repetition number ‘R_(max)’ for therandom access response reception.
 8. The UE according to claim 7,wherein the maximum NPDCCH repetition number ‘R_(max)’ is configured inthe UE through system information transmitted by the BS.
 9. The UEaccording to claim 7, wherein the random access preamble is transmittedin an RRC idle state, and the channel quality information is measuredbased on a common search space (CSS) used to receive the random accessresponse.
 10. The UE according to claim 7, wherein a first value isavailable for the UE as the required repetition number for thehypothetical NPDCCH, where the first value is larger than ‘R_(max)’, butnot exceeding the maximum value.
 11. The UE according to claim 7,wherein the channel quality information is measured for a non-anchorcarrier.
 12. An apparatus for a user equipment (UE) configured tooperate in a wireless communication system supporting narrowbandInternet of things (NB-IoT), the apparatus comprising: a memoryincluding instructions; and a processor operatively coupled to thememory, wherein the processor is configured to perform specificoperations by executing the instructions, wherein the specificoperations include: transmitting a random access preamble to a basestation (BS); receiving a random access response from the BS; andtransmitting channel quality information to the BS on a narrowbandphysical uplink shared channel (NPUSCH) based on the random accessresponse, and wherein the channel quality information is related to arepetition number required to detect a hypothetical narrowband physicaldownlink control channel (NPDCCH) at a 1% block error rate (BLER),wherein the required repetition number is represented based on a maximumNPDCCH repetition number ‘R_(max)’ for the random access responsereception, and wherein a maximum value which can be used as the requiredrepetition number for the hypothetical NPDCCH, is K times larger thanthe maximum NPDCCH repetition number ‘R_(max)’ for the random accessresponse reception.
 13. A method of receiving channel qualityinformation by a base station (BS) in a wireless communication systemsupporting narrowband Internet of things (NB-IoT), the methodcomprising: receiving a random access preamble from a user equipment(UE); transmitting a random access response to the UE; and receiving thechannel quality information from the UE through a narrowband physicaluplink shared channel (NPUSCH) based on the random access response,wherein the channel quality information is related to a repetitionnumber required for transmitting a hypothetical narrowband physicaldownlink control channel (NPDCCH) at a 1% block error rate (BLER),wherein the required repetition number is represented based on a maximumNPDCCH repetition number ‘R_(max)’ for the random access responsetransmission, and wherein a maximum value which can be used as therequired repetition number for the hypothetical NPDCCH, is K timeslarger than the maximum NPDCCH repetition number ‘R_(max)’ for therandom access response transmission.
 14. A base station (BS) comprising:a radio frequency (RF) transceiver; and a processor operatively coupledto the RF transceiver, wherein the processor is configured to receive arandom access preamble from a user equipment (UE), to transmit a randomaccess response to the UE, and to receive channel quality informationfrom the UE through a narrowband physical uplink shared channel (NPUSCH)based on the random access response, and wherein the channel qualityinformation is related to a repetition number required for transmittinga hypothetical narrowband physical downlink control channel (NPDCCH) ata 1% block error rate (BLER), wherein the required repetition number isrepresented based on a maximum NPDCCH repetition number ‘R_(max)’ forthe random access response transmission, and wherein a maximum valuewhich can be used as the required repetition number for the hypotheticalNPDCCH, is K times larger than the maximum NPDCCH repetition number‘R_(max)’ for the random access response transmission.